10 Striking Examples of Convergent Evolution in the Animal Kingdom

The success of a species is defined by its ability to adapt to change. All organisms need to develop the right biological characteristics to survive and thrive. For example, just like giraffes, the sauropod dinosaurs developed long necks so they could feed on foliage high above the ground. Similarly, birds and bats developed wings so they could fly, despite the fact that their last common ancestor lived hundreds of millions of years ago. These are just two examples of convergent evolution, a natural process by which completely unrelated species develop similar features as they adapt to similar environmental and ecological niches.

#1. Ichthyosaurs and Dolphins

Nobu Tamura

Few examples of evolutionary convergence are more striking than that of the Mesozoic ‘fish lizards’ and modern dolphins. Dolphins, being cetaceans, are much more closely related to giraffes and camels than ichthyosaurs. Nonetheless, though dolphins and ichthyosaurs evolved completely independently of one another some 200 million years apart, they look remarkably similar. This is because they lived in much the same aquatic environments, developing dorsal fins to help stabilize them while swimming. Many other aquatic animals, such as sharks and sailfishes, have also developed dorsal fins for the same reasons.

#2. Sparassodonts and Cats

Nobu Tamura

Sparassodonts were carnivorous marsupials from South America that looked remarkably like the now-extinct sabre-toothed cats. However, these strange creatures were metatherians, a group that appeared 125 million years ago. By contrast, placental animals like cats can only trace their lineages back some 65 million years, though true cats didn’t appear until much later. The similar appearance is a result of their statuses as apex predators of their environments. Sparassodonts ultimately died out facing competition from other carnivores that crossed into South America during the Great American Interchange 3 million years ago.

#3. Phytosaurs and Crocodiles

Nobu Tamura

Phytosaurs were a group of reptiles that lived during the Triassic Period, making them contemporaries of the early dinosaurs. Like crocodiles, phytosaurs were reptiles but, despite looking largely the same, that remains their closest taxonomic relation. The first crocodiles appeared over 70 million years later during the Cretaceous Period. Owing to their apparent similarity, palaeontologists first assumed that phytosaurs were crocodilian ancestors. However, it was later established that they evolved before crocodiles and birds went their separate ways down different evolutionary paths.

#4. Foxes and Thylacines

Helmut Diller

The last thylacine died in the early twentieth century, making their extinction one of the best known and tragic of such events in modern times. Although hunted to extinction, they were never great in number and, for the last 2,000 years, had only lived in the island of Tasmania. They’re also known as Tasmanian tigers, owing to their stripes. However, they looked more like foxes than anything else. Nonetheless, thylacines were marsupials rather than placental mammals like foxes, and thus had at least 65 million years to diverge down different paths. Like sparassodonts and cats, their apparent similarity was due to their status as apex predators.

#5. Hedgehogs and Echidnas

Pixabay

Hedgehogs and echidnas both have a protective coat of spikes, giving them a similar overall appearance. Nonetheless, the only thing they have in common is that they’re both mammals. Echidnas, which are only found in Australia and New Guinea, are monotremes, a bizarre order of very primitive and extremely ancient egg-laying mammals. Tracing their lineages all the way back to the Triassic Period, monotremes were among the first ever true mammals, appearing at around the same time as the first dinosaurs. Hedgehogs, by comparison, are placental mammals and are native only to Eurasia and Africa.

#6. Hyenas and Dogs

Pixabay

Hyenas are often assumed to be related to dogs, but they’re no more closely related to dogs than they are to cats or bears. While cats, dogs, bears and hyenas are all members of the carnivoran order, they’ve enjoyed around 40 million years of independent evolution. They also evolved thousands of miles apart in different continents. There are many different genera of hyena, both extinct and extant, and they perform a vital role is apex predators in many African ecosystems. Like other carnivorans, hyenas have evolved bone-crushing jaws and large teeth, making them highly efficient and successful predators.

#7. Tapirs and Pigs

Pixabay

Similar in shape and size to a pig and also herbivorous, tapirs are found in jungles and forests across South and Central America and parts of Southeast Asia. They’re perissodactyls, an order of animals that includes horses and rhinoceroses, although they look more like pigs than anything else. However, pigs are artiodactyls, which is the group that includes cattle, hippos, deer, sheep and goats. As such, pigs and tapirs belong to two mammalian orders that shared a common ancestor around 55 million years ago. Their similar appearance is a product of their similar habitats and lifestyles, particularly with regards to their love of wallowing in muddy pits.

#8. Hyracodonts and Horses

Charles R. Knight

Hyracodonts lived during the Eocene and Oligocene Epochs, disappearing around 23 million years ago. A very diverse and successful family, they came in many different sizes from the small, pony-like hyracodon to the colossal paraceratherium, one of the largest land-dwelling mammals that ever lived. Hyracodonts filled much the same ecological role as wild horses in that they were grazing animals that favoured environments like steppes and open forests. At the time, the equine ancestors of horses were barely larger than domestic cats, and modern horses only appeared around 2 million years ago.

#9. Mudskippers and Tiktaalik

Nobu Tamura

Tiktaalik, which was only discovered in 2006, is a creature with a truly remarkable story to tell. It is widely considered to be a direct ancestor of all land-dwelling life, since it represents the transition from fish to amphibians which, in turn, eventually led to reptiles and mammals. Although tiktaalik crawled out of the water in the Late Devonian, an incredible 375 million years ago, it looked a lot like a modern mudskipper. Both are amphibious fish, but the latter only decided to step out of the water hundreds of millions of years later. Today, however, mudskippers are among the few modern species of amphibious fish in existence.

#10. Placodonts and Turtles

Nobu Tamura

Placodonts lived during the Triassic, appearing at around the same time as the first dinosaurs some 235 million years ago. Like sea turtles, they lived among carnivorous marine predators. As such, to have any chance of survival, they evolved sturdy shells. Nonetheless, turtles didn’t appear until almost 100 million years later. Placodonts were a diverse reptilian order comprising several families. Among these, placochelys looked a lot like a modern sea turtle, while placodus looked more like a plesiosaur. One of the oddest members of the order, however, was the psephoderma, a turtle-like creature with two shells.