Generally speaking, you can look at a creature and tell if it is closely related to another animal. Wolves and dogs look alike and so do kangaroos and wallabies. But you can’t always judge a critter by its cover. Here are a few animal kingdom family ties that might just surprise you.
Seals and Bears
Image courtesy of nutmeg66's Flickr stream.
The cute and cuddly harp seal pup might look drastically different from its greatest predator, the polar bear, but biologically-speaking the two species are actually rather similar. Pinnipeds (the group containing seals, walruses and sea lions) evolved from a creature called the puijila, which is believed to have branched off from the ancestors of modern day bears. While the puijila looked like a cross between an otter and a seal, the carnivore’s strong legs and webbed toes indicate that it seems to have lived on land and hunted in the water – more like a polar bear than a modern day seal.
Image courtesy of Virginia DeBolt's Flickr stream.
While it can be hard to see the similarities between bears and pinnipeds, a quick look at the clawed toes of a seal and those of a bear (above) can show you that there is definitely some common genealogy between the two.
Elephants, Manatees and Rock Hyraxes
Image courtesy of gmacfadyen's Flickr stream.
Elephants are distinct-looking creatures, but they have a surprisingly large and diverse family. While at first glance it’s easy to think their closest relatives might be hippos or rhinos — the other large African creatures with gray skin— the truth is much stranger. So what critters are most closely related to these behemoths? Manatees and rock hyraxes, surprisingly enough.
Image courtesy of flickkerphotos' Flickr stream.
The manatee isn’t all that surprising. They are large, gray animals, too; they just happen to live underwater. Turns out, though, that manatees, rock hyraxes and elephants all shared a common ancestor that died out over 50 million years ago. That creature evolved into prorastomus, a mostly-terrestrial ancestor of the manatee and dugong that sought out underwater plants, eventually becoming the pudgy sea cows we now know and love.
Image courtesy of Tambako the Jaguar's Flickr stream.
That same common ancestor also started living in rocks and crevices in Africa, leading to a smaller body size and feet that were well-adapted to the rocky terrain. These creatures eventually became rock hyraxes.
Meanwhile, the elephant’s more direct ancestors continued to tromp across open land, allowing them to maintain their impressive size.
So just how drastic were the evolutionary changes from that common ancestor? Well, to put things in perspective, the rock hyrax weighs about 10 pounds, the manatee is about 660 pounds and the elephant is about 22,000 pounds.
Dolphins, Whales and Hippos
Image courtesy of krumbecker's Flickr stream.
Scientists originally believed hippos were most closely related to pigs since they have similar ridges on their molars, but DNA analysis shows that the semi-aquatic critters are more closely related to the fully-aquatic family of cetaceans –which contains dolphins, porpoises and whales.
Image courtesy of Alexandra MacKenzie's Flickr stream.
About 60 million years ago, hippos and whales had a common ancestor that eventually split into two groups. One branch became hippos and the other became whales and dolphins. The hippos are pretty close to that first splinter group, as they mostly looked like hippos, only skinnier and with smaller heads. Eventually, hippopotamuses evolved into their modern form and they remain the only surviving member of their order.
Image courtesy of Wikipedia user Nobu Tamura.
In the other branch, modern cetaceans look nothing like their ancient ancestors, some of which were carnivores that looked like swimming cheetahs, while others looked like weasel/hippo crosses and yet others looked like furry crocodiles. Most of their early ancestors had limbs instead of fins. It wasn’t until 40 million years ago that a whale ancestor that actually resembles modern whales appeared.
Rhinos, Tapirs and Horses
Image courtesy of Mrs TeePot's Flickr stream.
The rhino is another creature that seems like a relative of hippos or elephants, but is instead more closely related to horses. When you think about tapirs as a sort of link between horses and rhinos, the evolutionary story becomes a little easier to believe.
Image courtesy of Tom Raftery's Flickr stream.
While no fossils have been found of the common ancestor of these three creatures, a look at the animals’ recent ancestors helps make the connection. For example, horses only have one hoof now, but they once had three toes with large nails on them –just like rhinos. Scientists believe the common ancestor arose about 55 million years ago in what is now Asia, and then quickly spread throughout the continents.
Image courtesy of Jose Alfonso Palad's Flickr stream.
In the order of Perissodactyla, there were once many different creatures, some of which resembled rhinos, equus (the group containing horses, donkeys and zebras) and tapirs, but these are the only three families to survive to modern times.
Hyenas and Civets
Image courtesy of Marieke IJsendoorn-Kuijupers' Flickr stream.
Hyenas might look like dogs, but biologically speaking they’re a lot closer to big cats, which is why they are in the feliformia suborder. If that weren’t enough, despite their stripes and spots, they’re actually closer to mongooses than they are to tigers and jaguars. In fact, many of the hyena’s early ancestors looked a lot like modern civets.
Image courtesy of Tim Strater's Flickr stream.
Hyenas are also one of the only animals on earth whose females have a penis-like clitoris. One of the only other animals on Earth to have such an adaptation is the binturong (or bear cat), a member of the civet family.
Okapi and Giraffes
Image courtesy of Adam Fagen's Flickr stream.
Looking at the okapi, you’d be forgiven for thinking it’s related to zebras. After all, they have a similar stance and stripes. But the okapi is far more closely related to the giraffe. While the okapi has a noticeably smaller neck than a giraffe, their bodies are otherwise quite similar. They also both have small nubby horns at the top of their heads. The most noticeable common feature between giraffes and okapis are their flexible blue tongues that reach over a foot in length. Both creatures use this adaptation to acquire dinner – the tender leaves and buds from trees. The color is nature’s form of sunscreen – if you leave your tongue out all day, you certainly won’t want it to get sunburned.
Interestingly, the animals also share a common ancestor with deer and cows, meaning okapis really are nothing like zebras biologically speaking.
Do any of our biologist or zoologist readers have any other odd animal relationships you’d like to add?