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10 of the Strangest Yet Fascinating Animal Evolutions

6. Dogs were domesticated by humans in a remarkably short period. Therefore, they have evolved specific muscles that allow them to raise their inner eyebrows to manipulate the emotions of humans. The physiological change gave them expressive and infant-like looks, unlike wolves, their closest relatives.                                          

Dog
Dogs have evolved specific muscles that allow them to raise their inner eyebrows.

The tiny facial muscles on their face allow dogs to have an innocent look that produces nurturing response in humans.

Researchers say that these “puppy eyes” helped dogs bond better with humans after their domestication. They call this special anatomical change “expressive eyebrows.” Surprisingly enough, it was also found that humans produce similar expressions when they are sad.

It is also said that dogs with such traits have an evolutionary advantage, and humans show an unconscious preference to protect and breed them.

This process of facial changes only started after dogs were domesticated by humans and lived alongside them for thousands of years.

Studies say that this facial change was remarkably fast and is directly related to their enhanced social interaction with humans. (Source)

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7. Sea robins are deep-sea fish that evolved crab-like legs that are used by them as legs. These special legs have been evolved into tentacle-like digits after separating from the rest of the fin. It appears that the fish uses the evolved legs for walking on the seafloor, but actually it uses them for prey detection.

Sea robins
Sea robins

Sea robins are also known as “gurnards” because they make croaking noises while using their weird swim bladder. The legs that robins evolved from fins have a special ability to flex and bend in patterns that normal fins can’t.

On each side of their bodies, gurnards have six fin rays that are separated from the pectoral fins. Even if the primary use of tentacles is prey detection, they act as support structures.

The crab-like leg sensors detect chemicals that are released by invertebrates buried in the sand. The fish seem to devour anything it can get its hands on. Some of these include worms, shrimps, small fishes, crabs, etc.

Technically, sea robins are categorized in the same niche as catfish. However, because of the distinctive physical features of chin barbels, they look more like a predatory harp sponge. (1, 2)

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8. Hawk moths are the types of caterpillars that evolved to mimic a snake when confronted by predators. They have eye-shaped bright patches on their body that they flash towards the attacker when it is about to make its move. Sudden attention towards the eyespots surprises the bird or other predators. The moment gives caterpillars enough time to escape.

Caterpillars are easy, soft, and rich in protein – a good prey for animals like birds, monkeys, etc. One of the defenses that these tiny, helpless insects have evolved is snake imitation.

When an attacker encounters a snake’s eye-like patch, it surely gets startled for a moment, long enough for the prey to crawl away. At times, these eyes are enough to actually convince the predators that they are a real snake.

When a predator approaches, caterpillars with eye patches bulge their spots on the head in the predator’s direction. Suddenly, a helpless target appears to be a daunting snake.

One of the common caterpillars with such abilities is the elephant hawk moth. It has a scaly, snake-like pattern on its body and large eyespots on its head.

Another example is a tree-dwelling insect that is found in South America. This insect goes one step ahead by jabbing the predator, if needed, pretending to bite it. (Source)

9. In the deep and dark ocean, some fishes have evolved super-powered vision. On average, deep-sea fish have one to five RH1 opsins, genes that detect dim light. However, one species named ‘silver spiny fins” has rod cells that comprise 38 RH1 opsin genes to pick up the full range of bioluminescence.           

Silver spiny fins
Silver spiny fins. Image credits: uq.edu.au

Fish living in the deepest levels of the sea have a very low level of light exposure. The major source of light they receive is emitted by bacteria, shellfish, octopuses, and other fish.  This disadvantage has been overcome by evolution by increasing the number of genes for rod opsins. It is a retinal protein that detects dim light.

To understand how fish see this faint light, researchers examined the genomes of nearly 100 deep-sea fish. It was concluded that the protein opsin helps in capturing photons at multiple wavelengths. which means they see colors even in the dark sea.

Opsin enables the fish to detect varied wavelengths of light because it produces amino acid sequences.

Some of the common examples of fish with one to five RH1 opsin are the lanternfish and tube-eye fish.

The ability to see bioluminescent light provides the fish the dual function of avoiding predators and spotting prey at the same time. (1, 2)

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10. A fig wasp named Apocryta westwoodi grandi uses a zinc-tipped drill to lay eggs. This parasitic wasp has evolved into a zinc-tipped drill to bore into fruits. It penetrates the host fruit so that it can lay eggs inside it.

Apocryta westwoodi grandi
Apocryta westwoodi grandi. Image credits: JMK/Wikimedia

The female wasp of the species will first find a fruit containing larvae of other insects inside it. Then it will parasitize them to lay its eggs.

The tool that the wasp uses to drill to insert its eggs inside the fig is thinner than a human hair and has teeth filled with zinc. The tool is also called the “ovipositor” and is around seven to eight millimeters long. 

Zinc, the mineral, increases the hardness of the tool which affects the wear resistance of the drill bits. The researchers found that its teeth were as tough as acrylic cement which is used for dental implants.

They also think that the technique used by the wasp to drill the hole to deposit its eggs could inspire the design of new tools used for microsurgical techniques. (1, 2)

Also read: 12 Wild Animals That Seem Not to Be Dangerous, but They Actually Are

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