As humans, we are just one single species, but we are diverse creatures.
We have exploited nearly all regions on Earth and, as such, developed distinctive physical, and behavioral, traits that have allowed us to thrive in a specific area.
In other words, humans differ in appearances and behaviors across regions.
Even those who share a similar geographic range display different physical characteristics – such as hair color, eye color, or features (freckles, moles, etc). We have a sense of cultural identity and can express ourselves in the clothes or accessories that we wear.
However, animals look the same. Or, at least to us, they do.
You won’t find a tiger wearing a pair of glasses, or a dog with a face full of freckles. You won’t see one mossy leaf-tailed gecko that’s brightly colored and one that is dull.
If you look closely or have studied an individual animal in detail, you’ll begin to notice small physical characteristics that will enable you to identify the animal. However, to the untrained eye, all animals look the same. A tiger is a tiger. An elephant is an elephant.
But why do animals look the same?
Evolution is lazy. It finds the easiest way to adapt and overcome a challenge. As a result, many animals deploy similar mechanisms resulting in similar appearances. All tigers have stripes, blending them into their grassy habitat. All sea otters have thick fur, keeping them warm underwater. Most animals within a species will look the same.
Like us humans, animals in a specific region have evolved ways to adapt – either to find food, stay warm or escape predation. We’ll be exploring some of the reasons why animals look the same and what biological mechanisms are at play.
Reason 1: Camouflage
Also referred to as cryptic coloration, camouflage is a strategy used by a variety of animals to disguise their appearance, usually to blend into their surroundings.
Animal camouflage varies massively across the Animal Kingdom. Some animals have evolved bodies that resemble vegetation.
Some animals rely on group camouflage.
Other animals use camouflage to become invisible. By evolving a certain body coloration, animals can effectively become the surrounding vegetation. Animals such as stonefish and chameleons blend into their environment.
But why on Earth would an animal want to blend into the environment?
Well, quite simply, to avoid detection. And some animals are experts at this.
Take the mossy leaf-tailed gecko, for example. During the day this reptile, endemic to Madagascar, keeps its head down on a branch or tree trunk. Its flattened body looks as if it has moss and lichen growing all over it. As such, the mossy leaf-tailed gecko almost vanishes against the mottled coloration of the moss and lichen-covered vegetation.
Other animals use camouflage in rather less obvious ways. For example, on their own, zebras on the African plains stand out like a sore thumb. Their striking white body and black stripes (or is it black body with white stripes…?) do not appear to camouflage them against the dry and arid grasslands where they can typically be found.
However, zebras are not solitary animals. At least, they try not to be. Oftentimes, they can be found in large herds, thousands strong. With so many eyes on the lookout, predators trying their luck at an ambush attack most likely won’t get very far before they are spotted.
And when a predator is spotted, what do zebras do? They run! In every direction.
Now, imagine many thousands of black and white striped animals running all over the place. As a predator, it’ll be incredibly hard to focus on just one individual and plan an attack. Instead of just one moving individual, the predator is faced with a huge mass of striped movement; almost like an optical illusion. This is also called the dazzle effect.
Group camouflage is great, but one of the most impressive forms of camouflage out there has got to go to those species that can disguise their body as something else.
Leaves and sticks are a popular choice amongst a wide range of animals. As such, many different species can look the same – or, look like something else, depending on the way you see things.
The aptly named leaf insect is one such animal. Found across much of Southeast Asia and Oceania, leaf insects are perhaps the number one leaf impersonators in the Animal Kingdom. Some species disguise themselves as living leaves, whilst others take the more dead-like approach.
Whether it is a dead or alive leaf, leaf insects are experts at camouflage, and, as a result, all look remarkably similar.
And the same can be applied to stick insects.
This is a tried and tested method of camouflage, with approximately 3,000 different species of stick insects and around 30, that we know of, leaf insects. That is a whole lot of insects that look the same.
However, camouflage isn’t just used by animals hoping to evade predators. This tactic can also be used by predators to effectively hunt without being seen.
The Bengal tiger, known for its sharp teeth, is native to the dry forests and grasslands of India and surrounding countries. It uses its striped orange and black coat as a form of disruptive camouflage.
Disruptive camouflage is a form of camouflage that works by breaking up the outlines of an animal’s body.
The striped pattern of the tiger’s fur matches not only the long grass, but also the shadows cast by the sunlight filtering through the ecosystem. The stripes break up the tiger’s body shape, further aiding in its camouflage. This allows the tiger to slowly sneak up on prey without being detected.
Reason 2: Mimicry
Mimicry is the finest form of flattery. Apparently.
Well, evolution took this to heart and produced some truly outstanding animals that look almost the same.
But before we get into that, let’s first look at what mimicry is.
Mimicry within the Animal Kingdom is used when an animal’s physical appearance or behavior resembles another animal or its surroundings and benefits from doing so.
Mimicry is as complicated as it is fascinating, and it should really deserve an article all on its own. There are many different forms of mimicry, from aggressive mimicry to automimicry. However, for the purpose of keeping things simple, we’ll be sticking to two most naturally occurring forms of mimicry: Batesian and Mullerian mimicry.
Batesian Mimicry is a form of mimicry where a harmless animal mimics a dangerous animal. The mimic benefits, as it is often left alone by would-be predators, thinking it is a noxious or unpalatable species.
The most common form of this type of mimicry is through warning colorations. Otherwise known as aposematism, warning colorations are used to advertise an animal’s toxicity. This is the polar opposite of camouflage.
Take the coral snake, for example. This incredibly toxic snake, found across North and Central America, warns of its toxicity through a series of colors: black, yellow, and red.
However, kingsnakes, a completely harmless and non-venomous species, have evolved an incredibly similar pattern, using the same coloration as the toxic coral snake. This deceitful mimicry can only work if the number of dangerous animals outweighs the number of mimics.
Mullerian mimicry whereby two or more noxious, or dangerous, animals exhibit similar warning colorations. By looking the same, predators learn to avoid all animals that resemble one another, regardless if they are the same species or not.
Mullerian mimicry is most commonly observed across insect groups. However, ongoing research suggests that different taxa also display Mullerian mimicry.
For example, birds within the genus Pitohui have aposematic coloration – warning colors to advertise to predators to stay away. Unusually for birds, they are believed to be poisonous. Within their feathers, a powerful neurotoxic alkaloid can be found that will cause significant harm if ingested.
Native to New Guinea, multiple species of Pitohui overlap their geographical ranges and display near-identical colorations of black and reddish-brown.
But, back to insects. The group of animals where Mullerian mimicry is most evident.
Much research has centered around butterflies, and how certain toxic species look the same. Perhaps the most famous are the Heliconius butterflies.
Found throughout much of tropical and sub-tropical Americas, there are thought to be around 43 different species of Heliconius, with many more subspecies.
The wing patterns of each species of Heliconius are so remarkably similar, they were once thought to be just a single species. Each species has evolved wings to resemble a similar, toxic species in the area.
Reason 3: Convergent Evolution
So, we’ve said animals within the same species will often look the same due to evolution and selection pressures favoring certain characteristics.
However, animals in different taxa can also look similar.
Convergent evolution – when two or more non-related species occupying a similar ecological niche evolve and adapt as a response to acting selection pressures – is another acting force that sees animals look the same.
Confused? Don’t worry. We’ll break it down.
Let’s take dolphins and sharks, for example.
Sharks are fish. Dolphins and mammals. Two incredibly different groups of animals with over 200 million years of evolution difference.
Where sharks never left the ocean, the mammalian dolphins spent part of their evolutionary history on land, before returning to the oceans.
Being a mammal, the pectoral fin of a dolphin bears resemblance to the bone structure of a mammalian hand, including our own, complete with humerus, radius, ulna, carpals, and phalanges.
The pectoral fins of a shark, however, are comprised of just cartilage.
Anatomically, sharks and dolphins differ massively on skeletal composition. However, the fins of both sharks and dolphins have evolved to carry out the same function – steering, propelling, and stabilizing themselves within the water – and therefore they look remarkably similar to one another.
Another example of convergent evolution is flying animals, such as birds, bats, and insects.
Similarly to dolphin fins, the wings of bats and birds are comprised of bones, in varying proportions, the same as most other mammalian bones. Insects, on the other hand, do not have bones. Instead, their wings are composed of cuticles, arranged in veins, membranes, and chitin.
Wings are a form of convergent evolution. Many different species across a range of taxa have wings for the same purpose: flight (although, not all birds and insects can fly). Although these species all have wings, they did not share a common ancestor that had wings. Wings evolved independently.
And, from a distance, many of these animals look the same.
The bee hummingbird, the world’s smallest bird, and the hummingbird hawk moth, an insect, look similar, especially when they feed on plant nectar by hovering mid-air, beating their wings at insanely fast speeds.
Reason 4: Inbred Genetics
Sometimes, humans intervene with nature with dire consequences.
The Florida panther, native to the swamps of South-eastern North America, was all but hunted to extinction due to human-wildlife conflicts. In the 1970’s only 20 remained in the wild.
Conservation efforts brought these numbers from the brink of extinction to a couple of hundred. However, there were some secondary complications that caused most Florida panthers to look the same.
As the gene pool was so low, owing to just a few breeding individuals, inbreeding occurred. As a result, many Florida panthers we see today all have kinks in their tails and “cowlick” fur.
Over millennia, evolution has created animals that look the same by means of camouflage, mimicry, and convergent evolution.
Though it is unlikely you’ll ever see a rhino look like a chicken, there are many animals on our planet that do look the same.
Some, such as the Batesian mimics, look the same as dangerous animals to reap the rewards of being left alone, without having to invest time in energetically costly toxin creation. The Mullerian mimics, on the other hand, spread out the price of toxicity by all resembling one another.
Other animals have evolved a similar color pattern on their bodies, allowing them to blend seamlessly into the surrounding foliage and vegetation.
Environmental selection pressures can also have an effect, allowing non-related animals to look the same to perform a specific task in a specific ecological niche.
So, next time you see an animal, think. Are you looking at the real thing, or is it an imposter?