Sea lions might share part of their name with a big cat, but they’re actually more closely related to dogs! Sea lions are part of the big group of meat-eating animals called Carnivora– the carnivores. Carnivores are split into two sub-groups: the ones that are more closely related to cats, called feliforms, and the ones that are more closely related to dogs, called caniforms. Sea lions, along with seals and walruses, are caniforms. Like dogs, wolves, and bears, they tend to have long snouts and claws that don’t retract.
Sea lions do have some things in common with lions, though. They’re good hunters, and they’re very social animals that live in large groups. When they’re in a group together on land, they’re called a colony, and in the water, they’re called a raft. Breeding groups of sea lions are called rookeries.
Photo by Reywas92
Scientists need to be able to tell the individual animals they’re studying apart, and the zookeepers at the Seneca Park Zoo have a new idea about how to do that. Scientists often tell animals apart by tagging them, but that can be stressful for animals. So, zookeepers are finding new ways. They’ve been analyzing the whisker patterns of sea lions to see if they can tell the animals apart by looking at their whiskers instead of by tagging them. You can read more about their efforts here!
Photo by Kelli O’Brien
When we think of dolphins, we often picture sleek gray animals that are about ten feet long. However, the biggest dolphins in the world are more than twice that size– and they might look different that you’d expect. The world’s largest dolphins are actually orcas, also known as killer whales.
Orcas reach lengths of up to 26 feet and can weigh up to six thousand pounds– more than a rhinoceros. Orcas are apex predators, meaning that they are hunters that live at the top of the food chain. They eat fish, seals, and even other dolphins!
Photo by Christopher Michel
The biggest dinosaurs in the world belong to the sauropod group– the giant, four-legged, long-necked plant-eaters. It’s hard to tell exactly which species was the biggest, since it’s rare to find complete dinosaur skeletons. Scientists have to use the pieces they do find and use them to estimate what the entire body size would be.
A recently-discovered dinosaur just might be the biggest known to science– a titanosaur called Patagotitan mayorum. This dinosaur reached lengths of over 120 feet long and likely weighed 76 tons, making it quite possibly the largest animal ever to walk on land. However, there are even bigger animals in the ocean– the blue whales alive today weigh 300,000 pounds!
Illustration by Levi Bernardo
Scientists at zoos work to protect all kinds of animals, from ones found on the other side of the world to ones right in our backyards. At the Lincoln Park Zoo in Chicago, scientists study wild Eastern massasauga rattlesnakes to help conserve the species. These snakes live in wetlands and grasslands around the central United States, and every spring, Lincoln Park Zoo scientists head a few hours out of the city to count the rattlesnakes. The scientists place harmless tracking devices in the snakes, similar to microchips for dogs and cats, and measure the snakes to get a better sense of what makes for a healthy snake habitat. In a recent trip, they found fifty snakes in just a single day!
Most snakes are relatively small, but there are a few species out there that are enormous. The biggest snake in the world is the reticulated python. Reticulated pythons, which are found in Asia, can reach lengths of close to thirty feet, and can weigh up to 350 pounds. Even newly hatched reticulated pythons are two feet long. These snakes are not venomous, but instead kill their prey by squeezing it to death, a process known as constriction.
It is very rare for these reticulated pythons to pose a danger to humans, though. Meanwhile, the most venomous snake in the world, the inland taipan, is far smaller—around 6 feet—but has enough venom in one bite to kill a hundred people. Inland taipans are shy, though, and rarely come into contact with people.
Photo by Bernard Dupont
Dolphins are some of the world’s most beloved animals– these intelligent, social sea mammals are popular in zoos and aquariums. Most of the dolphins in zoos are sleek, gray bottlenose dolphins, the most common members of the dolphin family. But there are dozens of species of dolphins– they come in all shapes and sizes. The world’s smallest dolphins are Maui dolphins, also known as popoto, which only reach five and half feet long and a 120 pounds. The world’s biggest dolphins are killer whales, which can reach over thirty feet in length. (Fun fact: all dolphins are technically whales.)
Dolphins don’t just come in gray, too. Dolphins can have a wide range of black and white markings, and some dolphins, like the ones in the Amazon River, are pink!
Photo by Jorge Andrade
If asked to explain what a snake is, a lot of people would probably say, “a reptile with no legs.” But that’s not quite right—while all snakes are legless reptiles, not all legless reptiles are snakes. Meet the legless lizards.
Legless lizards look a lot like snakes—many of them have scaly, snakelike skin, and they don’t have legs, so they move by slithering or burrowing in the earth. But there are some key differences that have shown scientists that legless lizards aren’t snakes—they’re part of the reptile family that includes four-legged lizards like geckos, but over time, they “lost” their legs to better suit their lifestyles. Their skeletons still show traces of these lost limbs—it’s a little like how human ancestors lost their tails, but we still have tailbones at the bottom of our spines. Some legless lizards have tiny little nubs where their ancestors had legs.
Some of the strangest legless lizards don’t even look that much like snakes—they look more like worms! Their scales are small and smooth, and they live underground, where they eat insects and larvae. But despite their appearance, these animals are still lizards!
Photo by Richard Avery
King cobras are some of the most well-known snakes in the world. They’re the longest venomous snakes in the world– adults are often up to 13 feet long, and the largest one on record was over 19 feet! Their venom is strong, but they are afraid of people and hunt rodents, lizards, and other snakes.
In addition to their venomous bite, king cobras are known for the beautiful appearance– they have “hoods” on their heads and sometimes have bright yellow chevron stripes. You can see one here at the Philadelphia Zoo— a female born in the wild in Indonesia in 2003. See how she’s flicking out her tongue? Snakes do that to “taste” tiny scent particles in the air to get a better sense of the world around them!
One of these things is not like the others. At first glance, this looks like a group of dinosaurs. There’s a massive Tyrannosaurus rex on the left and a three-horned Triceratops on the right—some of the most well-known dinos. However, towering at the back of this group is a creature that lived among the dinosaurs, but wasn’t one: Quetzalcoatlus.
Quetzalcoatlus was a pterosaur, a flying reptile that lived millions of years ago. (You might hear this group called “pterodactyls,” but that’s an outdated term.) Pterosaurs aren’t dinosaurs—they were distant relatives. Why aren’t pterosaurs considered dinosaurs? The distinctions might seem small to non-paleontologists—little features on pterosaurs’ thighbones, shoulder blades, hips, and backbones set them apart from dinos!
Illustration by Durbed
Circus acts have made white tigers famous—these striking felines’ black stripes stand out against their white coats, and they have dazzling blue eyes. But while white tigers are beautiful to look at, they’re a sign of poor breeding practices that are bad for the animals.
White fur in tigers is the result of a rare genetic mutation. In the wild, white tigers are rare, because the odds are slim that two unrelated tiger parents would carry the mutated gene that results in a white cub. However, some people have bred closely related tigers or even purposely bred white tigers to produce white offspring. This isn’t good for the tigers; the genes that cause white fur are related to medical problems.
Good zoos that are committed to protecting animals don’t purposely breed white tigers. Instead, they work to build a diverse gene pool that produces healthy offspring for generations to come. Besides—healthy, orange tigers are beautiful too!
Photo by Tony Hisgett