Why don't fish have neck?

Fish have gills and fins, but they have no neck. This is partly because, having a neck shaking from side to side in the water will make it difficult to swim fast.

In addition, any creature called fish, by definition, cannot have neck. According to experts, by the time a fish-like creature developed an neck, it was categorized into another animal.

The first neck of the organism was recorded as belonging to Tiktaalik roseae , a species that appeared on Earth 375 million years ago, in the Devonian period. Scientists describe T. roseae half a fish, half a 4-legged animal.

Instead of having the neck, fish possesses a series of bones that connect the skull to the shoulder belt, which is attached to the fins.

Ted Daeschler, a paleontologist at the Institute of Natural Sciences at Drexel University in the US, said that instead of having neck, fish possesses a series of bones that connect the skull to the shoulder belt, which is attached to the fins.

"Shoulder belts are bone-like components of the collarbone and shoulder blades, which support the front part, whether it's a fin or a limb. In fish, they connect not only very tightly, but also create into a bony surface , " explained Daeschler.

Over time, a number of fish species began to change shape, such as lobster fin, including finfish - a group of ancient fish that are thought to be extinct until the fishermen rediscover. They were off the coast of South Africa in 1938. According to the fossil record, the lizardfish species over time have lost some of the bones associated with the skull.

The researchers looked at a 2.7-meter-long, lobed fish T. roseae. However, it completely lost the bones that connected the skull to the shoulder belt and instead developed an neck. This neck is more likely to help it turn its head faster to breathe or hunt in shallow water-like environments. In contrast, when there is no neck, the fish will have to move the entire body to bring the head forward in a certain direction.

The fossils revealed, the first creature on Earth has a neck called Tiktaalik roseae, a half-fish species, half-breed 4-legged animal.(Photo: cbc.ca).

So is Tiktaalik completely fish or 4-legged animals? According to paleontologist Daeschler, this is an intermediate stage of evolution , lasting about 20 million years, to see this strain evolve from lobed fish into a four- genome amphibian. Scientists call it "gray zone" , when some parts of an animal evolve, but some are still in their original form.

The animals have ancient advantages. They can quickly navigate the mouth without having to move the entire body.In fact, all early 4-legged animals were predators. However, according to Mr. Daeschler, many fish species are also predators and they are very successful when there are no necks.

However, whales and dolphins are thought to have lived on land before relocating to the water. Once grown back into marine animals, whales and dolphins have significantly shortened their neck vertebrae, making their entire neck short and hard, instead of long and flexible.

Experts say that the long and flexible neck is not suitable if the organism moves in the water, because the head is pulled by the water pressure. Therefore, having no neck will make the fish swim better in the water.