When different organisms have a similar trait, one possible explanation is that they inherited the trait from a shared ancestor. For example, cats and lizards both have four limbs because the last common ancestor of cats and lizards had four limbs. However, some traits arise by convergent evolution, meaning that a similar trait evolved independently in two groups whose last common ancestor did not share that trait. An example of this is flight in birds and bats—it’s been over 300 million years since the reptile lineage leading to birds split from the mammal branch leading to bats, and that ancient, heavy-set lizard-ish ancestor definitely didn’t fly. Therefore, bird and bat wings are the result of convergent evolution, meaning each group has evolved wings independently.
Finding examples of convergent evolution is of interest to many biologists because it helps us uncover patterns in how structures evolve. Although they both have wings, birds and bats construct those wings very differently and use them in different ways. Studying these kinds of convergent traits lets us explore the realm of what’s possible (both feathers and skin-flaps supported by the arms can be used for flight) and what’s probably not (for example, we haven’t found any animals that fly by modifying their tails into propellers).
As an evolution nerd, my all-time favorite kind of convergence involves mammals that are highly specialized ant- and termite-eaters. Ants and termites are an interesting food source for large mammals because they’re so tiny that an animal has to eat thousands to get any nutrition at all. Luckily, both ants and termites are closely-related social insects that live in huge colonies/lunch buffets! Species that prey on these insects have evolved many times throughout the mammal family tree, and they share some bizarre adaptations that let them thrive on their specialized diet. Here are a few of my favorites:
Fig. 1 A giant anteater (Myrmecophaga tridactyla) displaying its specialized tongue. Image source: Wikimedia Commons.
Giant anteaters are amazing creatures found in Central and South American forests and savannahs. (Even though they are called “anteaters”, they also consume termites!) Their ant-based diet differs from that of their closest relatives, the sloths, who are dedicated plant-eaters. Since they don’t need to chew their prey, giant anteaters have long narrow skulls, extremely thin jaws, and no teeth. They feed by using their enormous front claws to rip open termite mounds and tear bark off of tree trunks, then deploying their long sticky tongues to snag the insects inside. These anteaters have special musculature that allows them to flick their tongues in and out over 150 times per minute! .
Fig. 2 The aardvark (Orycteropus afer) is another ant and termite specialist with a scientifically adorable snout. Image source: Heather Paul via Flickr.
The aardvark is another ant and termite specialist that shares many traits with the giant anteater, such as powerful forelimbs and a long, sticky tongue. However, aardvarks belong to a much older branch of the mammal family tree, and these similar features are a result of convergent evolution. Aardvarks forage for termites on the African savannahs, and scientists used to assume they were most closely related to giant anteaters and sloths. However, new studies indicate that aardvarks share a common ancestor with other African mammals such as manatees, elephants, and hyraxes . Like the anteaters, they use powerful forelimbs to dig open termite mounds, have long cone-shaped skulls, and snag termites with their sticky prehensile tongues; unlike the anteaters, they actually have teeth! However, these teeth lack enamel (the hard outer surface that protects the tooth from damage) and are extremely soft. Rather than chew its food, the aardvark has a muscular stomach that acts like a gizzard to grind up insects after swallowing .
Fig. 3 The aardwolf (Proteles cristata) is like the hyena’s smaller cousin who won’t stop talking about how great it feels on this amazing all-insect diet. Image source: Dominik Käuferle via Wikipedia.
Despite its similar name, the aardwolf is separated from its fellow termite specialist the aardvark by millions of years of evolution. This African mammal belongs to the hyena family (part of the larger group Carnivora that includes dogs, cats, and bears), and it looks like a travel-sized, pointy-faced, less threatening hyena. Apart from their sharp canine teeth (used mostly for looking tough and defending territory), aardwolves have tiny reduced tooth nubs where their bone-cracking relatives have terrifying blade-like molars. Their skulls are also longer, flatter, and weaker than a hyena’s. Like the giant anteaters and aardvarks, aardwolves use long sticky tongues to consume exclusively termites .
These three mammals are just a few examples of species that have convergently evolved specializations for feeding on ants and termites—there are many more! Ant-eating is a great example of convergence because it has evolved multiple times in very distantly related animals. In each case, species show similar adaptations to their specialized diet, including long conical skulls, reduced or absent teeth, and exceptional tongues. These traits make sense when you think about the functional demands of their diets—they need to be able to insert their snouts into insect colonies and slurp up thousands of insects daily in order to survive on such tiny prey, but they don’t need to bite very hard or chew very much.
Finding these connections between body shape, behavior, and diet is my favorite part of studying evolutionary biology in animals. When extreme modifications like this pop up in different parts of the mammal tree, it’s always interesting to think about why a particular set of traits is best suited to a certain feeding strategy. Many animals eat insects as all or part of their diet, but these convergent ant and termite specialists have taken it to a whole new level.
If convergent evolution lights your fire, tell us your favorite example of a convergent trait in the comments and we can discuss it!
Naples, Virginia L. “Morphology, evolution, and function of feeding in the giant anteater (Myrmecophaga tridactyla*).” *Journal of Zoology 247 (1999): 19-41.
Seiffert, Erik R. “A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence.” BMC Evolutionary Biology 224 (2007).
Richardson, P.R.K. “Aardwolf: The most specialized myrmecophagous mammal?” South African Journal of Science 83 (1987): 643-646.
More From Thats Life [Science]
- Things That Glow Pink in the Night: Why do some animals have fluorescent coloration under ultraviolet light?
- When You Call a Fish a Frog
- Who’s Got the Biggest Genome of Them All?
- The Biology of Booze ft. Tequila
- Dying Tomatoes, Healthy Kittens, and the EMP500: Why you should care about the International Society for Microbial Ecology
- The Purebred Poodle Problem
- Let It Glow
- I’m Likin’ That Lichen
- Celebrate the Holidays with a Decorative Parasite
- Sleeping One Hemisphere at a Time
- Through the Mycologist's Hand Lens: Deceptive Decomposers
- Life Science in Outer Space!
- 5 Things You Didn’t Know About Rats
- Watermelon Snow
- Critter Candid Cam
- Three Cool Plants in Hot Places
- A parasite only a moth could love
- Telling tales of plants and their names
- The Colorful World of Primate Hair
- Where do fish go in winter?
- You Scratch My Back and I’ll Scratch Yours
- Alien Microbes: How studying hyperthermophiles can help us discover life on other planets
- Life, the universe, and everything: Dreams of being a biophysicist
- Bug Sleuth – One Entomologist’s Mission to ID a Mysterious Swarm of Wasps
- Horny and Hungry: The Dilemma of Sexual Cannibalism
- Who’s who? The elusive difference between butterflies and moths
- Tuberculosis - A Romantic Disease?
- Ode to a Few Arachnids
- Monotropa uniflora - This wildflower is pretty wild
- Eavesdropping in the Animal Kingdom: Sneaky Creatures Just Trying to Get Ahead
- Trypanosomes - A Weird Pathogen You Haven't Heard Of
- A Beautiful 9/11 Tribute, but a Fiasco for Migratory Birds
- Cats can have AIDS, too.
- Part 2: Does catching Pidgeys help you notice Pigeons? Interviews with Pokémon Go Researchers
- Biodiversity in my Backyard: Encounters with Pidgeys and Dratinis, Part 1
- Fins, Limbs, Rays, and Digits – A Beginner’s Guide to Terrestrial Living
- Fins, Limbs, Rays, and Digits – A Beginner's Guide to Terrestrial Living
- Five things that really stink about the Brown Marmorated Stink Bug
- Tricks but no Treats - An Orchid’s Guide to Making a Fool of Your Pollinator
- Tracking the lost years - where do baby sea turtles grow?
- Posing as a Bird Mama: the adventures of a researcher-turned-bird-parent
- Hot moves and sexy sons · When Boys Become Men By Dancing
- The hungry caterpillar in real life
- Mantis Shrimp Vision - Seeing in Secret Code
- When It Comes to Bird Beaks - Size Matters
- Is your gut trying to kill your resolve? · Mind over microbe
- Recent talk of walls in the media has brought up a lot of emotions, but what do walls do in nature? · When a Wall is just a Wall
- Bees are more than buzzing insects around you · May the Bees Be With You: Maintaining the Sweet Balance in Life
- Neither a toad nor a worm · Nematodes: The super microscopic animal!
- Snap! Flash! Bang! Find out how ocean-dwelling pistol shrimp fire bubble ‘bullets’ to stun their unsuspecting prey. · How Pistol Shrimp Kill with Bubbles
- Who needs males after all?
- Ecology and Behavior of Woodchucks · Opposition Research on My Garden’s Greatest Nemesis
- Vision in Jumping Spiders · Watching Your Every Move
- Slimed and Consumed - The Blob is Real!
- The Evolution and Ecological Impacts of Cats · Lion in Sheep's Clothing
- What happens when frogs have to compete for acoustic space and a chance to be heard? · Struggling to be Heard - Competition in a Complex Soundscape
- Think Genghis Khan and Napoleon were the most successful invaders? Think again. · Invasive Species and Invasion: Part 1
- When, and how, terror birds invade
- 8 Reasons Plants Are Amazing
- Too Clean for Comfort · How our obsession with cleanliness might be hurting our health
- Stop, evaluate, and listen - serotonin surges when a female is present
- No Teeth, Long Tongue, No Problem - Adaptations for Ant-eating
- The Good, the Bad, and the Ugly - Predators, Parasitoids, and Parasites
- How our microbiome affects our health and vice versa · If you don't care for your microbiome, you might want to start
- Finding new ways to grow bacteria to progress science · Culturing the Least Cultured Members of Society
- Hit the Road Jack
- What Happened to Your Nose?
- Building better plants - Norman Borlaug and the Green Revolution
- Love Songs for Nobody - Birdsong in Winter
- We know we get infections from time to time. Why does this happen? · The Evolution of Virulence
- How cheese rinds may be a valuable tool for microbial discovery · The Unseen World – On Cheese?
- Find Me Where the Wild Things Are
- A commentary on how to make science more ‘clickable’ · You won’t believe this simple trick to tell if your coral is healthy or not
- Some species hide in plain sight, but scientists have ways to suss them out · Cryptic Species Hide in Plain Sight
- Minuscule Hitchhikers Pinch a Ride · Creature Feature - Pseudoscorpions
- World Fish Migration Day 2016!
- Walking With Giant Anteaters
- Why we should care about sea turtles · When A Sea Turtle Balanced Earth
- More ›