Hippopotamus: Hippo Biology & More!

The chunky champion of charismatic megafauna is a famous yet understudied animal. Spending most of their days lounging in the water, and nights eating grass to fill their massive bodies, the hippopotamus is a wonder of Africa. These giants normally mind their own business, but you do not want to cross paths with either. Surprisingly fast and incredibly strong, these animals can be quite deadly if you get too close to them. It turns out the key for how to survive a hippopotamus attack is mostly to stay well out of their way, and find cover if you happen to be charged on land. We also wanted to learn more about these fascinating beasts, so we found an expert!

In this video, Kirstynn from the Untamed Science team chats with PhD and hippo expert Camille Fritsch all about hippos, how to avoid an attack, their conservation, and more! 

What is a Hippo? 

Dozing quietly through hot summer days in the water, and consuming mass amounts of vegetation on land at night, this seemingly “amphibious” gigantic mammal is not to be underestimated!

Hippo for short, hippopotamus belong to the Order Artiodactyla and Family Hippopotamidae. There are actually only 2 extant species of Hippos, the Common Hippopotamus (Hippopotamus amphibius) and Pygmy Hippopotamus (Choeropsis liberiensis). This page will focus on the common hippo. 

The common hippo is found in pockets throughout most of Africa, except for the Northern countries where they are now extinct, such as Egypt. You will always find them near bodies of water, and they are now primarily found in protected areas, though they are not restricted to them like some other organisms, since they can travel down river ways that are impossible to fence in! 

Hippos are very large mammals. Large males can get to a height od 5.2 feet, 16.5 feet long and 9,900 pounds! Their large tusks can also reach 1.5 feet! 

2 hippos with their eyes out of the water. Hippo biology

Hippo Biology Basics

Hippos live about half of their life on land and the other half in the water. These mammals are mostly considered nocturnal, because they come out of the water to feed at night, and spend the hot days resting in the water.

They are herbivores, mainly eating grass but also being known to browse. They are also Considered “ecosystem engineers” for their massive consumption of grass and the fact that they move a lot of nutrients, mainly from the land into the water. 

Believe it or not, like many herbivores, hippos can eat meat when the opportunity arises. This is especially true for easier to digest and rich-in-nutrients parts from a corpse, such as the intestine of an already dead animal. This being said, from what we understand so far, they aren’t active predators, instead just occasionally eating meat if it is convenient. 

Hippos live in a group of animals called a pod (that’s right, just like whales) where a dominant male and some sub-dominant males will live with their group of females. Female hippos mature reproductively at about 3 years old. A fun fact about this is that if conditions are not favorable the year that a hippo should be ready to mate, it will delay reproductive maturity until the next breeding season! Breeding season is in the dry months and hippos will give birth just 8-10 months later! One of the fastest gestation periods of any large land mammal. 

Are Hippos Dangerous? 

The short answer is yes, absolutely. Though these big lumbering mammals look quite docile, and even quite cute, trust me when I say you do not want a hippopotamus for christmas! Hippopotamus are considered one of the deadliest large land animals. Though they have nothing on mosquitos for the number of people killed per year, it is somewhere near 500 deaths by hippo per year. These are large animals that are surprisingly fast and extremely strong. Also, though we don’t like to label animals as “aggressive” they can be quite territorial, and during mating season, or when protecting their calves, they definitely need their space. 

How Fast Can A Hippo Swim? 

You might be surprised to find out that hippopotami don’t actually swim! Instead, they walk and bounce along the bottom of the water. They can however hold their breath for around 6 minutes! With this in mind, it can be a good idea to make some noise while you are on the water so you do not accidentally startle one, causing it to attack in defense. 

How Fast Can a Hippo Run? 

Any hippo expert will tell you that hippos are actually extremely agile on land. Able to run at 18-25 miles/hour (30-40 kms/hr), scale up steep river banks, and swing around their large heads, hippos are to be taken quite seriously.

hippo runs with helicopter shadow in the background. Hippo biology
Avoid a Hippo Attack 

Long story short, give the animals their space, and always travel with an expert! Hippos have killed people and can cause problems for locals, especially in rural areas where people need to fish alongside hippos in their habitat, but in the scheme of things, hippo attacks are usually avoidable. As Camille says in the video, giving them plenty of space is usually more than enough, and traveling with an expert guide in hippo territory can help you stay safe. If one does charge you, you probably won’t be able to outrun it, so look for cover or climb a tree, as you probably won’t be able to outrun one! 

In short, the best way to survive a hippo attack is to avoid it all together by giving them plenty of space!

Hippo Conservation 

Like many large land mammals, their biggest threat is loss of habitat, land use change, and because they spend so much time in the water, leaching of pesticides and excess fertilizers into water. You can help hippos by participating in Ethical and sustainable tourism in Africa 

The IUCN red list considers them Vulnerable with a stable population trend, thought the story is a bit different in each area. Groups such as the IUCN SSC Hippo Specialist Group are a great source of information for what is being done to protect hippos! 

hippo biology researcher works on a tranquilized hippo

What Can You Do? 

Sustainable tourism and donations to organizations that protect hippo habitat can help these animals to thrive. If you are looking for a place to check out hippos and get a behind-the-scenes look at research in Africa, you can head out with Camille and their tour group Imvubu Safaris

Tiger Oscar

Oscar fish, also known as “Tiger Oscars” and “marble cichlids”, are popular freshwater fish that belong to the cichlid family. Their beauty, intelligence, and good manners make them pleasing fish for the aquarium. However, they have a high temperament, which makes it difficult to house them in a community tank. That is why it is recommended that you have some fish-keeping experience before owning one.

Oscars are native to South America (Brazil, Peru, Colombia, and Ecuador). They prefer slow-moving water with lots of rocks and debris.


Oscar fish have brown or black bodies with orange or red marks or marbling. Some varieties also have olive or green bodies. They have large heads, mouths, and eyes. The fins are fan-shaped that extend the length of their body.

When the fish is born, its colors are dull but they begin to become brighter as it grows.

Oscar Behavior

Oscars are intelligent fish that love to swim with purpose around the tank. They can recognize their owners and can be hand-fed.

However, they have territorial tendencies, so you should carefully choose the fish you house along with it in a community tank to prevent stress among the fish. If Oscar fish sense their territory is being invaded, they will attack their tank mates. They are also known to fight with the fish of their species, especially during the breeding season.

Oscar Lifespan

The average lifespan of the fish is somewhere between ten to thirteen years. If you take proper care of the fish, it can live for more than fifteen years.

Fish Caring Tips

It is easy to replicate their freshwater tropical habitat. Though you need to be extra cautious when housing them with other fish in a tank. When living in a community, they need a large tank, and consistent water parameters to stay relaxed.

Feeding Oscar Fish

Oscar fish eats a variety of small fish, larvae, and plant matter in the wild. You should replicate the same diet in captivity. Feed them a variety of live foods like brine shrimp, pellet foods, and plant matter to keep them healthy and away from diseases.

Split their feeding sessions into two to three times a day and feed the amount they can finish in two minutes.

Tank Requirements for Oscars

It is important to replicate Oscar fish’s natural habitat in the aquarium with warm water and varied plant species. You need to introduce a soft, and sandy substrate with debris, vegetation, and rocks scattered on the top to make them feel at home. You can also add tank decorations such as caves and java moss to replicate their natural habitat.

Oscars are fond of digging in the substrate so decorations must be placed firmly in the tank.

Suitable Tank Mates for Oscar Fish 

Oscar fish are used to being surrounded by other fish in the wild, but the tank has limited space and this can lead to fights and fin-nipping. So, it is recommended to house them alone. If you want to house them together or with other fish, go for a large tank (at least a 55-gallon tank upto 125 gallon) and add an extra 30 gallons for each fish you want to keep.

In a community tank, choose a passive fish that won’t disturb the Oscar fish. The most suitable tank mates for them are:

  • Fire-mouth cichlids
  • Jaguar Cichlids
  • Bichirs
  • Green Terrors
  • Silver Dollars
  • Convict cichlids

Oscar Fish Breeding

It is difficult to breed them in captivity as the fish is picky about its mates. Putting a male and female in the same tank in the right conditions does not always guarantee success. You can take these steps if you are adamant about breeding them:

  • Select a mature male and female fish (The fish that has achieved the age of two is mature).
  • Place both male and female Oscar in separate tanks decorated quite similarly to the home tank. Reduce the temperature by a few degrees to mimic the rainy season of their natural habitat. Oscars breed during the rainy season and this can encourage them to breed.
  • Keep fish in a good mood, feed it live and frozen foods and keep the surface of the tank aerated.
  • If the pair is interested in each other, they will flare their gills and vibrate their tails. If they are not interested, they begin to fight. If this happens, separate them and try with another male or female.
  • Oscar fish lays up to 3000 eggs after successful breeding and parents will guard them until they hatch.
  • Remove the parents, after eggs have hatched to prevent them from eating their babies.

Pro Tips

Never house Oscars with fish of smaller size, as it will eat anything smaller than its size.

If you are thinking of setting up a tank for a single fish, Oscar fish is a great choice. However, for community tanks, we recommend aquarists gain some experience before keeping an Oscar fish as it can bully or eat other fish smaller than itself.

Chinese Wisteria

“In times of stress, that’s when this plant flowers.”

A reflective note about Wisteria after hanging out with it : It doesn’t need good soil – it can grow practically anywhere because it can fix nitrogen – it has what it needs. In fact, it grows better when there is trauma – when conditions are the worst – it sends out more vines and blooms, draping vast landscapes with brilliant purple inflorescences. It has something beautiful and powerful to show the world, but first it must climb its way up to the light.

Take a look at the wisteria video we made to get an overview of this amazing plant.

How Toxic is Wisteria?

The toxicity of wisteria is from glycosides in the plant named wistrin and lectin. It’s found in all parts of the plant, but in small quantities doesn’t seem to be much of a problem. That’s why there are many reports online that you can actually eat the flowers. I tried 4-5 while making the wisteria video above and found that it started burning my throat slightly and gave me a stomach ache later in the day. Thus, it seems advisable not to make these a regular part of your diet, even if a flower or two won’t hurt you.

The part with the most toxicity is the seeds and seed pods. Do not try to ingest these as they will make you sick, sometimes for up to a week. Eating wisteria and the seed pods can cause poisoning in pets. Dogs in particular should stay away from eating wisteria. But, I should note that on the greater scale of what should or should not be in your yard, this is far from problematic and it’s relatively safe given that the seeds don’t actually taste good at all.

How to tell if you have Chinese, American or Japanese Wisteria

Technically there are 9 species of wisteria but the most common are the Chinese, Japanese and American wisteria plants. So, I’ll give the basics on how to tell which wisteria you have.

Chinese Wisteria flowers early – March, April or May. It starts before there are any leaves on the vine. The color can change, so don’t look at that so much. Also, look at how it twists up the tree. If you’re looking down at the ground, the direction of twisting up the tree is counter clockwise – refer to the video above.

Japanese Wisteria has the largest inflorescences. However, that doesn’t help much if you’re in the woods. There is no way to compare two plants to each other. The easiest way to tell a Japanese Wisteria is simply by looking at the twisting direction. The Japanese wisteria will twist in a clockwise direction as it goes up the tree! How cool is that!

American Wisteria flowers later – late April to June in most places. The flowers are smaller, but again, that’s not super helpful if you haven’t seen a lot of different types. The big key is that it flowers when the leaves are fully out on this plant! Also, it’s good to look for counter-clockwise twisting. Only the Chinese and American ones do that.

Where is Wisteria Found?

The wisteria vines are native to North American, China and Japan. Now, they’ve been spread all over the world and are even considered an invasive weed in some areas. However, from my experience and a bit of research, it seems they don’t spread well from seed, which means it more or less spreads only by suckers. If you have an established plant somewhere, it can take over a small patch. If not, it’s hard for it to cause big problems. That’s a good thing for such a beautiful plant.

Making Rope from Wisteria

I made a longer article about making rope from wisteria here on StoneAgeMan. However, this is the gist of it in this short video.

Eastern Rat Snake

The Eastern rat snake, also sometimes referred to as the black rat snake, is a common inhabitant of the deciduous forests of the eastern US. Other than the rare indigo snake, it is the largest snake in its range. Full grown rat snakes have few predators other than humans.

Where is the rat snake found?

The Eastern rat snake ranges from New England south to Florida and west to Texas and Minnesota. It is found commonly in wooded habitats, such as deciduous and pine forests. It can also be found in river floodplains, rocky hillsides, farmlands, and open fields. They often find their way under houses or into barns where they’ll feed on the resident rodent population. As the above video shows, they’re also very adept at climbing high into trees.

Similar Species to Rat Snakes

The species most commonly mistaken for the rat snake are black racers. The image below is of a southern black racer, which are generally smoother in appearance and faster on the ground than rat snakes. Notice the scales around the mouth. In racers the white patch is confined to the chin. You can see small differences in this closeup photo. Rat snakes also have keeled scales, meaning their scales have a ridge down the center of them (which may or may not extend to the tip). This makes them rougher to the touch.

Color Patterns in Eastern Rat Snakes

There is quite a large color variation that you can find in eastern rat snakes. They’ll range from totally black to grey with black patches.

What does the Eastern rat snake eat?

The primary prey for these rat snakes are rodents, birds, and birds’ eggs. They’re often seen eating chicken eggs or climbing trees to eat small bird eggs. Occasionally they may eat voles, squirrels, and chipmunks.

Conservation of Rat Snakes

The Eastern rat snake is listed as as species of least concern. They’re one of the most abundant snakes in the central and eastern US. However, that doesn’t mean they’re free from any danger. Like all snakes, they’re affected by roads, where many of them are killed. They are also in danger because of habitat loss throughout their range. Fortunately they are well adapted to find mice and rats in and around dwellings.

Learn more about the Eastern Rat Snake

Yellow Fever Mosquito

Aedes aegypti is a vector for transmitting several tropical fevers. Only the female bites for blood, which she needs to mature her eggs. To find a host, these mosquitoes are attracted to chemical compounds emitted by mammals, including ammonia, carbon dioxide, lactic acid, and octenol.

The yellow fever mosquito can also contribute to the spread of reticular cell sarcoma among Syrian hamsters.

The mosquito carries a disease that is widespread in tropical South America and Africa, and often come out in moderate regions during the summer time. Today, the Aedes aegypti is found around the southeast region of the U.S., but is slowly decreasing due to competition with other mosquitoes, such as Aedes albopictus.

Asian Tiger Mosquito

Aedes albopictus was first reported in Europe in 1979 in Albania. In 1985 it was reported in Texas, USA and has since spread northward and eastward, having now been reported in at least 32 US states including Hawaii. This expansion was facilitated by the movement of used tyres along the interstate highways. In Latin America it was first reported in Brazil in 1986 and later in Mexico in 1988. In Africa, it was first detected in 1990 in South Africa but establishment was only reported in 2000 from Cameroon.

After entering the United States almost twenty years ago, Aedes albopictus has spread throughout much of the eastern states. The mosquito was most likely transported along highways and other major roadways in shipments of used tires imported from other countries for retreading. On January 1988, the U.S. Public Health Service required all used tires entering the U.S. from known endemic countries be dry, clean and treated with fumigants. Surveillance for Ae. albopictuswas initiated in 1986 and this species continues to be monitored by public health agencies.

Management of adult populations is more complicated than for other species due to insecticide tolerance to malathion, temephos and bediocarb (Morbidity and Mortality Weekly Report 1987). In many suburban areas, complaints to health departments are more frequently due to Ae. albopictus than in former years when Ae. aegypti was the most commonly reported nuisance mosquito. Source reduction is an effective way for people in the community to manage the populations of many mosquitoes, especially container breeding species such as the Asian tiger. The removal of mosquito breeding habitat can be an effective method for mosquito control.

Eliminate any standing water on the property, change pet watering dishes, overflow dishes for potted plants, and bird bath water frequently. Do not allow water to accumulate in tires, flower pots, buckets, rain barrels, gutters etc. Use personal protection to avoid mosquito bites. Long sleeves and insect repellent such as DEET will reduce exposure to bites. The Asian tiger mosquito is a day biter with feeding peaks early morning and late afternoon, so by limiting outdoor activities during crepuscular periods (dawn and dusk) when mosquitoes are generally most active, bites can be avoided.


Emerald Ash Borer

The emerald ash borer is known by entomologists by its acronym: EAB. If you’re an insect aficionado or a tree lover, you likely already know this name. For the rest of you, it’s a name you will know soon enough. It is the cause of arguably the most catastrophic tree death event in the history of North America.

We just finished a 3 month deep dive interviewing EAB experts from around the country and compiling a list of things you need to know about EAB so we can all help scientists mitigate this problem. First, let’s get you up to speed with this short (and may I say, fun) video.

Biology of the Emerald Ash Borer

The emerald ash borer is a small wood-boring beetle in the family Buprestidae. While there are thousands of wood boring beetles in the world, most cause no problems at all. They add life to the forest and actually perform helpful biological processes for us. This is not the case for this invasive insect. That is in large part because it was introduced to North America where it has no natural predators and its food (ash trees) has no natural defenses. Below is a snapshot of an adult beetle.

This is the adult phase of the beetle that can fly around, mate and lay eggs on ash trees. From these eggs, the larvae hatch. It’s this life stage that causes the real problems. It feeds just under the tree bark on the phloem tissue. Just look at the growing size of these feeding trails on this (now dead) ash tree trunk.

As these feeding trails coalesce, it completely cuts off the tree’s ability to transport nutrients to other parts of the tree and it dies.

When did EAB arrive in North America?

The answer to this is tricky because nobody saw an infected shipment en-route to the US. However, in 2002 EAB was detected in Michigan in ash trees near Detroit. Likely, these insects caught a ride on some shipment into Detroit in the year or two prior. They jumped ship from packaging material and found a tasty ash tree to lay their eggs. The infestation we see now has spread entirely from this small introduction at the turn of the decade.

Now, we are looking at an invasion of 33 US states and several territories in Canada.

Where Did Emerald Ash Borers Come From?

The Emerald Ash Borer (EAB) is actually native to Asia including China, Korea, and Japan. In its native land it does feed on native asian ash trees. However, the ash trees there seem more resistant to this beetle. In Asia, there are also several predators that have co-evolved with these beetles. This acts to keep the population size down and minimize its effect on the ash trees there.

How Much Has EAB Spread Now?

This map shows the current range of the emerald ash borer as of the making of this video.

The range and spread of the beetle is updated every month by entomologists and can be found via this emerald ash borer monitoring site.

How can you help?

Although the invasion is well underway and quickly covering the east coast of the US, there is still hope. We can learn from the destruction that has already occurred and help mitigate the damage in areas that it is spreading.

Here’s what you can do:

Identify An Ash Tree

Ash trees are easy to identify and they’re more common that you might think. This is the leaf of an ash tree.

Notice that each leaf has several leaflets that come off the main leaf stem. The main trees that look similar to ashes in the US are hickories. If you nee more help identifying your tree, I’m going to point you to this resource.

What If My Tree Dies From the Emerald Ash Borer?

If a tree dies from the emerald ash borer it can still act as a food source for the beetle. That is a huge problem for the other trees in the area. First, let someone know that your tree has died – especially if you are in an area that is not known to have EAB. Secondly, to prevent the continued spread of this bug in your area, these dead trees should be chopped up and destroyed.

Treat Hi-Value Ash Trees with Insecticide to Kill EAB

If you find a tree that shows signs of dying or EAB has been found in the vicinity, you can treat trees to help save them. Treatment is only effective if done early or before infestation has progressed too far. In the later stages of attack the insecticide may not work to save the tree. I went out with Dr. Andrew Loyd, an arborist with Bartlett tree research laboratory in Charlotte NC to help give me a better picture of what kind of insecticide is being used and how it is applied.

Diversify Your Trees

We never know what the next invasive pest or pathogen is going to be. The key to protecting our cities and forests is working to increase diversity. This diversity will both help slow the spread of pathogens and it will allow us to have some resilience when something does kill a particular species of tree.

Find Insect-Resistant Trees

This infestation will likely kill 99.99+ percent of the ash trees in the country. Yet, amidst this destruction there will be survivors. Scientists need to know about these trees that have this magical set of genes that allow them to resist the emerald ash borer. If you find an ash tree that should have died, but has not, let someone know. It may be the beginning of the next generation of ash in America!

Don’t Move Firewood

It’s true, the emerald ash borer adults can fly. That means it will move without out help. But, it won’t fly more than a mile or two every year. That slow spread of this insect means it’ll take decades to centuries for it to naturally cross the country. That spread is unfortunately amplified when people toss infested wood into their vehicles and carry them on highways for hundreds of miles. For example, EAB just showed up in Denver Colorado. It didn’t fly there. Someone brought it in infested firewood! It’s an easy thing you can do to help. Stop moving firewood!

More Great Resources on the Emerald Ash Borer

Special Help with This Project

This project was a collaboration between a ton of different people and groups. We wanted to point out everyone who helped us create this resource here.

  • Jeff Eickwort at the Florida Forest Service helped us find financial resources to make this film to help Florida residents understand what is coming and have a set of simple tools to put into action to help slow its spread as it approaches.
  • Dr. Jiri Hulcr is the forest entomologist at the University of Florida. His guidance and expertise in finding various experts for the film was the only way this film was made. He also provided his skilled storytelling ability throughout the narrative. Without him, the project wouldn’t have gotten off the ground. Also special thanks to Dr. Andrea Lucky and the Hulcr family for being tour guides  as we drove around town getting all this footage.
  • Dr. Lynne Rieske-Kinney is the forest entomologist at the University of Kentucky. She helped organize the amazing crew on the ground in Lexington where all the trees were falling. Thank you to all of the amazing crew on the ground there for helping us get some stellar footage of tree-falls.
  • Dr. Jason Smith is a forest pathologist at the University of Florida / IFAS who gave us a ton of information about solutions in ash tree health moving forward.
  • The Hulcr lab at the University, had a ton of fantastic people who helped get macro shots of these beetles. In particular, Dr. Andrew Johnson spent two days with us in the lab getting these macro shots.
  • Dr. Andrew Loyd at Bartlett Tree Research Laboratories gave us a detailed walkthrough of treatment solutions for ash trees.
  • Haley Chamberlain and Jonas Stenstrom served as the photographers and filmmakers on this project. It was directed by Rob Nelson.
  • Our patrons here helped us fund the creative outreach projects that linked to this, such as the how-to-photography video, the gimbal video and the ash tree treatment videos. Those videos help us do so much more with projects like this. A special thanks goes to Tobias Haase, Dennis Horn, Medesthai, and Johanna van de Woestijne for their extra support.

Blue Shark

There are many different sharks living in our vast oceans, and they have a wide range of shapes, sizes, life cycles, and diets. However, today we are talking about one of the most abundant and widespread of these beautiful and diverse creatures: the blue shark.

What is a blue shark?

The blue shark (Prionace glauca) is a long and slender predatory shark with a lengthy yet rounded nose. An adult blue shark can grow up to 12.5 feet (380 cm) long! The females are usually between 5.6-7.2 feet long (173-221 cm), and the males are 6-12.5 feet long (182–380 cm).

Their coloration can be described as indigo blue along their dorsal area (upper part of their body), with metallic blue flanks (their sides), and a bright white underside. They also have very large, round-shaped eyes, and of course, a lot of teeth.

Where does a blue shark live?

The blue shark is one of the most abundant shark species within the pelagic zone of the ocean (open water away from the coast). This means they usually are found away from the coastline, unless the continental shelf is particularly narrow in that area.

As well as being the most abundant shark, they are the most wide-ranging. Blue sharks can live in both temperate and tropical waters, which range from 53.6ºF-68 ºF (12-20 ºC). The geographical range of this abundant species is from latitudes of 60 ºN and 50 ºS! Because of this, blue sharks are found off of every continent except Antarctica. In terms of vertical range, they can be found from 350 m in depth all the way to the surface.

What do blue sharks eat?

Blue sharks can be considered apex predators within their ecosystem, meaning they are at the top of their food chain. The blue shark is a more active hunter at night, but they have been observed feeding throughout an entire 24-hour period. Their primary diet consists of small fish that live in open water or on the ocean floor, invertebrates (such as squids), other small sharks, and even seabirds!

What is the life history of the blue shark?

Since the blue shark is so widespread, the exact timing of their life cycle varies depending on the region, but the general story is the same. The blue shark has a long life and can live to be 20 years old. However, they sexually mature (can mate and produce offspring) between the ages of 5-7 years for females and 4-6 years for males.

Blue sharks have very complex and lengthy migration patterns (which can include transatlantic migrations!) for a few reasons. First, females and males tend to spatially segregate throughout most of the year; they live in different parts of the ocean except for when they come together to mate. Secondly, after mating, females migrate to new areas to give birth to their pups (baby sharks). Lastly, tracking data has also shown us that blue sharks of different ages/sizes do not reside in the same areas, so after giving birth female adults will also leave that area.

Once mature, the two sexes will come together once a year to mate. Female blue sharks are able to breed every year, although it is uncertain if they always do. During courtship, the males will bite the females repeatedly, which has resulted in females having skin three times as thick as males!

Interestingly, after mating, female blue sharks can store a male’s sperm to delay fertilization until the time is right! Once the eggs are fertilized the gestation period is between 9-12 months; this is how long it takes the offspring to develop. The variance in gestation period is due to the fact that the mother sharks can also delay the birth of their pups to make sure they are born in the ideal environment. Blue sharks are what is called “placentally viviparous” which means the young develop inside of the uterus and are born live, just like in placental mammals! Litter sizes average around 30-35 pups but can be as large as 135! They are born at around 14-20 inches long (35-50 cm), and they will reside in their “nursing grounds” for around two years before beginning to segregate, based on sex, and move to new habitats that better suit them.

Are blue sharks dangerous to humans?

Sharks tend get a pretty bad reputation with humans as dangerous death machines, but how dangerous is the blue shark really? Well, the blue shark is one of the most abundant sharks out there, but according to the International Shark Attack File (ISAF), there have only been 13 unprovoked shark bites from blue sharks, 4 fatal, since the year 1580, a relatively low rate for a span of 438 years. Blue sharks have also been described as “curious,” and they will approach humans without much hesitation, helping to illustrate that they bite and/or attack rarely when compared to the number of encounters with humans. Now, this is not to say that you should not be wary of sharks and respect their distance in the wild, but we should also understand that they are not the bloodthirsty monsters that the media may portray.

How are blue sharks important to their ecosystem?

Since blue sharks are at the top of their food chain, they are very important in regulating the ecosystem in which they live. Apex predators help to control populations of the different organisms that they eat, which generally allows for greater biodiversity, because competition between different prey species is not as intense with lower numbers of individuals. If an apex predator is taken out of an ecosystem, the species it preys upon may have the potential to increase to higher levels than normal, which can cause many problems.

First, it increases the competition and pressure on other species that share the same habitat and maybe eat the same food as that prey species, which can cause declines in the other species. Secondly, the prey species itself can lead to its own demise through multiple mechanisms, such as an increase in disease with a greater population size, or the potential for the population to grow large enough to wipe out their own food source, and later crash to very low numbers, or possibly go extinct.

What threats are there to the blue shark?

Blue sharks are large and powerful apex predators, so what do they have to be afraid of? Similar to many aquatic species, the blue shark is vulnerable to various different natural predators when it is in its juvenile stages, when they are a bit more snack-sized. Additionally, there are some that claim orcas also feed on mature blue sharks, but the most commonly used report in this claim was unable to specify what exact species of shark it was… so the jury is still out.

The largest threat to the adult blue shark is, you guessed it, humans. Blue sharks are under threat from intentional harvest, sport fishing, and from by-catch, organisms that are caught and killed accidentally when humans fish for another species. However, sport fishing is likely the lesser of these threats as shark catch-and-release survival rates have shown to be upwards of 90% in some sharks. Additionally, there have been restrictions put on the harvest of blue sharks (see below), but they are still harvested in much of the world for their meat, primarily their fins.

What is the conservation status of the blue shark?

Currently, the blue shark is listed as Near Threatened by the IUCN. The species does not meet the criteria of being vulnerable, or worse; however, with the current available data and population trends it is likely to be moved into a worse category in a short amount of time. It is thought that perhaps the blue shark is quite resilient to fishing pressure, as they have large litters of pups and are so widespread, but their long lives and slow maturation may also make them vulnerable to extinction. Additionally, there is some evidence of decline of populations over the years, which may illustrate that they are indeed threatened by human harvest. Due to this uncertainty, the IUCN website and other wary scientists say that the blue shark needs to be re-evaluated and possibly placed in a different conservation category, after better information is collected on their population status and biology.

With this information you may be curious, why is the status of the blue shark so uncertain? First off, marine organisms are extremely difficult to get accurate data on, as you could imagine, because they are in the ocean and difficult to observe. Most of the data that we get on population numbers for sharks, and other marine organisms, comes from the “catch per unit effort” or CPUE; which essentially is number, or total weight, caught per amount of fishing effort (boats, hours fishing etc.) on that species. Usually this number is calculated from intentional and accidental harvest. There are many problems with this method that make marine populations difficult to estimate, including the fact that a lot of harvest, whether accidental or intentional, does not get reported to the organizations that are taking the data.

Another issue with tracking blue sharks is due to their intense migratory patterns that were mentioned earlier. A lot of research has been done on how much these sharks move, and where, but there is still a lot of uncertainty in this area, adding to the difficulty of knowing how many there are, where they are, and how we can best protect them.

What is being done for the blue shark?

For sharks in general, there is a rising awareness and support for the need to protect them. Many countries are doing their part by setting up “shark sanctuaries,” areas that completely ban fishing of sharks. Other countries have at least banned shark finning, requiring fisherman to return with and use the entire carcass of a shark, which helps to reduce overall catch of sharks. Additionally, many nations have set up more general Marine Protected Areas (MPAs) that help protect the crucial habitat of many marine species. There has also been a rise in the commitment of governments and scientists to better track fishing practices to allow for more sustainable fisheries worldwide.

Though there are issues with many of these practices, such as loopholes around fishing regulations, non-compliance (ignoring fishing regulations), or MPAs not being large enough to protect all of the sharks’ habitats, the efforts to begin more sustainable harvesting practices and to protect sharks is on the rise.

How can we help the blue shark?

First off, increasing education about sharks and their importance to our oceans is key to increasing support for their protection. We can also increase shark protection by advocating for government officials and parties to implement policy that allows for sustainable harvest and trade of sharks in their waters. Additionally, joining conservation organizations such as Shark Defenders can help to show support for sharks and help to spread education for shark protection awareness. Shark Defenders also has some more tips on their page on how you can help sharks, such as ecotourism with sharks in countries that support shark conservation or reducing consumption of shark-related products.

Gopher Tortoise

The gopher tortoise is a burrowing reptile native to the southeastern United States that over time has experienced great habitat loss and population declines. Currently, it is listed as Threatened in most of the states where it occurs and is listed as threatened under the Federal Endangered Species Act (ESA) in the western portion of its range and the populations in the east have also been petitioned for listing as threatened. The biologists who study this interesting reptile want to be proactive in stopping it from being listed on the ESA but not for all the reasons that you might think. Watch this video we made at the Jones Center at Ichauway to find out more about how the gopher tortoise is an important keystone species and how fire plays a surprising role in maintaining the ecosystems where they live.

What is a gopher tortoise?

The gopher tortoise (Gopherus polyphemus) is a land-dwelling reptile that tends to be a grayish brown/black in color, though their appearance varies slightly between regions. They usually grow to an average of 10 pounds (4.5 kg) and 10 inches (25 cm) long, however, they can be can grow up to 15 pounds (6.8 kg) and reach 15 inches (38 cm) long!

The gopher tortoise gets its interesting name from the fact that they dig burrows, and they spend most of their lives inside of these burrows, which can end up being about 40 feet (12 meters) long! The front legs of the gopher tortoise are specialized for digging and are covered in thick scales, whereas the hind legs are described as “elephant-like” to give them some serious pushing power.

Where do gopher tortoises live?

The gopher tortoise is endemic to the southeastern United States (they live only here and nowhere else). The eastern range of the gopher tortoise is eastern Alabama, Florida, Georgia and southern regions of South Carolina, while the western, federally listed part of the range, includes western Alabama, Mississippi, and Louisiana.

These tortoises need habitat with dry sandy soils – soils that are ideal for digging. They also prefer habitat with open canopy cover, where lots of sun can reach ground level, and support a diverse range of plant species. Some examples of these natural habitats include longleaf pine forests, pine scrub, pine flatwoods, coastal dunes and grasslands, and dry oak sandhills. Additionally, they make use of anthropogenic landscapes, such as old pastures, roadsides, and the clear-cut areas produced for power lines, provided the soils are well-drained. To highlight one of the ideal habitats for the gopher tortoise – the longleaf pine forests – we made this short video at the Jones Center at Ichauway.

What do gopher tortoises eat?

Their herbivorous diet is quite diverse, but in general they consume grasses, berries, legumes, and low-lying fruits. This is one of the reasons gopher tortoises require habitat where sunlight reaches the ground level, because it aids in the growth of the vegetation that they rely on.

Digestion of these foods by the gopher tortoise requires that they bask in the sunlight, because they are ectotherms. Ectothermic species maintain their body temperature, activity, and metabolism by their environment, and they need to warm up their bodies with the sun to get the digestive process going.

Why do gopher tortoises burrow?

Burrowing serves a few purposes for gopher tortoises, including avoiding predation, maintaining a stable temperature, and defense from fires that frequently burn through their habitat.


Adult gopher tortoises have few predators because of their protective shell. However, tortoises are sometimes collected for food, although this practice is now illegal. Young tortoises have a wide range of predators, such as snakes and foxes, and burrowing helps them to avoid many of these threats. However, as with many species, the eggs and young are a lot more vulnerable to predation than adults.

Ectothermic Species

Because tortoises are ectotherms and their metabolism is reliant on the environment around them, burrows maintain a stable temperature year-round, so the tortoises can avoid extreme cold or hot temperatures. To raise their body temperature, tortoises emerge from their burrows and bask.


In addition to avoiding normal environmental fluctuations, burrows can protect the tortoises from natural disturbances, such as fire. The ideal habitat for tortoises tends to experience frequent fires, as these fires help to maintain open canopy cover, which in turn gives the tortoises access to sunlight and plenty of the variety of ground plants that they eat.

What is a gopher tortoises life cycle?


The gopher tortoise has a long life-span and matures late in life, just like many other tortoises. If they can avoid disease and being eaten, they can live >50 years. They are mature at around 10 – 20 years old, at which point they can begin to reproduce. They are highly social and often occur in clusters which facilitates mating interactions.


Females lay their eggs underground in open areas, like the entrance to their burrows, where the warmth from the sun can help aid in incubation. On average a female lays about 6 eggs each year. Eggs will incubate in the nest for about 100 days, but this varies slightly depending on region and climate. Interestingly, sex in developing Gopher tortoises, like many reptiles, is determined by the temperature at which the eggs incubate. More males are produced from warmer incubation, whereas more females occur when incubated in cooler temperatures. The parents do not provide any care to their young after they lay and bury the eggs. Reproductive success is generally low in gopher tortoises, meaning that many of the young do not survive to maturity (long enough to have babies of their own), however, over a female’s life span she produces many eggs and in a stable environment, some of her offspring likely survive to replace her in the population. In disturbed environments, the delayed maturity and high egg and juvenile mortality makes them even harder to protect.

Why are gopher tortoises an important keystone species?

The gopher tortoise can be considered a keystone species because they have a large impact on the ecosystem they live in relative to their abundance (they do a lot compared to how many of them there are in an area). This is because the burrows that they dig are used by approximately 360 additional species that share their habitat! This can be especially important during the frequent fires that occur in these habitats, as other animals use the burrows as shelter from the fire. Some of these species include small mammals, invertebrates, frogs, and a large variety of snakes, many of which are quite rare (e.g. the indigo snake as shown below).

What are the threats to the gopher tortoise?

Anthropogenic disturbance is the major threat to the gopher tortoise. First, habitat loss due to land-use change and development (such as urbanization and agriculture) has greatly decreased the amount of suitable habitat for gopher tortoises. This development also increases contact with humans which increases mortality, largely due to roadkill. Additionally, tortoises are threatened by humans catching tortoises to keep as pets or even to eat them.

What is the conservation status of the gopher tortoise?

The gopher tortoise is listed under the Endangered Species Act (ESA) in the western portion of its range and has been since 1978. The eastern population has been recently listed as a candidate for listing, which means it warrants federal protection but due to a bottleneck in the listing process, things are on hold. In the meantime, a voluntary agreement called a Candidate Conservation Agreement has been established where there will be an increase in cooperative conservation pending a final decision on listing. The hope is that these actions will halt or reverse the declines in this species. The current conservation status of tortoises varies among states, but it is illegal to harm tortoises in any part of their range. (See this FSW page for more information).

How you can help the gopher tortoise?

The conservation and management of habitat for the gopher tortoise is the key to helping them thrive in the wild, so encouraging elected officials to help preserve this crucial habitat is a good start. Additionally, if you are a private landowner within these regions you can cooperate with the following organizations, such as The Nature Conservancy, Gopher Tortoise Conservation Initiative, and the Natural Resources Conservation Service (NRCS), which has a landowner incentive program to preserve tortoise habitat. See links below:

To learn more about gopher tortoise research, visit the website of The Jones Center at Ichauway (featured in the above video). As an option you can find someone and pay someone to write your research paper on similar topics. Or you can contact the U.S. Fish and Wildlife Service for information on prescribed burning, or other ways in which way you can help restore and maintain prime gopher tortoise habitat. Also, just as any other wildlife species, if you see them in the wild, appreciate them from a distance and do not remove them from their home where they are their healthiest and happiest.

Learn More: Gopher Tortoise Researchers

Informational Sources on the Gopher Tortoise

Other Videos We Filmed in the Gopher Tortoise Habitat

360 Degree Images from Gopher Habitat

Burning of a Longleaf Pine Forest

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Herpetologists at the Jones Center

Haley, Lora, and Jen with a Pine snake

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Entrance to Ichauway – The Country Store

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Hellbenders are the one of the largest aquatic salamanders in the United States and have a face that only a mother could love. Their heads are flat and circular, topped with eyes that seem too small for their bodies. At 12 – 16” in length, they far outsize what most imagine when the term salamander comes up. Although they are not aggressive, hellbenders do have a mouth full of tiny teeth. And the North Carolina Zoo’s Curator of Reptiles and Amphibians Dustin Smith thinks they’re awesome.

“The coolest thing about them is their bodies. They have this really flat head that they use to get under rocks. Then they have this rudder-like tail that helps propel them through these very fast-moving streams. They have these skin folds on their sides that help them absorb oxygen,” says Smith. “They’re just a really cool species! We’re lucky enough to have them in North Carolina, the salamander capital of the world. We have more species of salamanders than anywhere else. They’re charismatic, especially if you look at their behavior.”

Silted Out of House and Home

Hellbenders favor fast-moving streams with plenty of clear water and large rocks for shelter and nesting. Smith says that many rivers are degrading because they’re near very busy roads, causing problems with runoff from the roads or nearby agriculture fields. As soon as silt begins to accumulate in the streams, the hellbenders can’t use them anymore. “They’re getting pushed out of their homes by silt.” He cites a recent study that shows that in some areas as much as 50% of the hellbender population has disappeared.

“Hellbenders are part of the largest variety of salamanders in the world and can be two feet long. In Asia, there are some that are over four feet long. They’re massive, and people think they’re very, very impressive. Sadly, hellbenders been persecuted because people think they’re toxic or demonic or things like that. Anything we can do to teach people about them is something I’m very interested in.”

Hellbender Box: from the Zoo Made for Two

Dustin Smith and Untamed Science’s Haley Chamberlain Nelson are talking near a stream. They’re both in waders and in front of them is what looks like a dinosaur egg molded from cement. The object is actually a nest box, and it’s about to be deployed in the stream as part of the Zoo’s effort to learn more about the hellbender.

“Although we’re looking at a lot of different tools in our conservation toolbox, this is the first one that we’re attempting, because it’s fairly easy to place these boxes in streams,” says Smith. “We’re assuming it will take them one to two years to start using them.” The boxes, each weighing in at a hefty 100 pounds, will be partially buried in substrate with rocks placed on top of them. There is a PVC pipe protruding at one end that forms the entrance to the box and will face downstream, both to resemble the real hellbender habitat and to prevent the entrance from silting up.

At the top of the box, scientists have installed a cap that can screw off, allowing them a look at the activity inside while causing a minimal amount of disturbance. Even with their substantial weight, Smith says heavy storms will still sometimes dislodge them. “We’re hoping to get better at predicting the ideal habitat design.”

“We’ll measure them, weigh, and sex them. That’s how we know whether the population is growing;, and we also look for juveniles. There are lots of different components to it.”

Conserve Like Hell

Protecting the health of the hellbender habitat is also going to protect a whole host of other animals, says Smith. The salamanders feed on crayfish, shiners, macroinvertebrates, and even trout. If a given area is a productive hellbender habitat, that means the region must be healthy enough to sustain its prey as well. Thus, the water is healthy and the system is balanced.

Smith likens the search for ideal hellbender habitat to a treasure hunt. “When we’re searching for these, we’re snorkeling through streams like this one. You find that iconic rock, this big rock. No matter which state you’re in, you just see that one rock, and think, ‘That’s the ideal rock.’ When you look underneath, or you lift the rock and you find a hellbender, it’s like finding the pot of gold!”

Ultimately, Dustin Smith says much of the conservation responsibilities will fall to the local human population. “The people who live around the rivers are going to be the ones doing most of the work. They’re the ones who are saving water and saving the species for us to continue working with the hellbender.”

Hellbender FACT PACK

Size: 12 – 15”, though they may be as long as 29”. Another salamander species in Asia may be 48” long.
Age: Sexually mature at five to eight years old; life expectancy is 12 – 15 years, and up to roughly 30 years in captivity.
Range: Southwestern New York to Georgia and Alabama
Mating habits: Annually, and normally lay around 250 offspring. Parents have been known to eat their own fertilized eggs.
IUCN Status: Near threatened due to habitat loss.
Fun fact: No one is sure how they got their name, but one theory is that fishermen named them hellbenders because they look “like they crawled out of hell and are bent on going back.” They are also called “mud cats,” “devil dogs” and “snot otters” — named for the mucus they secrete through their skin when threatened.

More Hellbender facts: