Why do giraffes have such long necks?

Why do giraffes have such long necks?

In the animal world, we find many species that have unique characteristics, which in many cases make them remarkably particular. An example of this is the giraffes, which are native to Africa and are distinguished by being the tallest land animals that exist. Giraffes are ruminant mammals, so their diet is exclusively herbivorous, for that they use their huge neck, eating exclusively plants that no other animal can reach unless they can climb.

 

Giraffe neck characteristics

When we see a giraffe with a neck that can measure up to 2 meters, we can think that its internal anatomy is totally different from that of other artiodactyls or ungulates, the order to which these animals belong. However, studies [1] have shown that giraffes, like other mammals (with the exception of three genera), have seven cervical vertebrae. Therefore, his long neck did not affect, at least structurally, his spine.

The main differences the giraffe have in their vertebrae have to do with certain transverse holes and significant elongations of the vertebral centres, which finally explains why they have such a long neck. In this sense, and despite differing opinions, giraffes have a backbone with the same number of structural units, but clearly more elongated.

This results in more than half of the giraffe’s spine being made up of elongated cervical vertebrae. While the other vertebrae in the spine are similar in length to other ungulates.

In this sense, the giraffe’s neck is an adaptive aspect of this animal that makes it unique and despite the various postures for the reasons of this evolutionary result, it is estimated that environmental limitations must have played an important role in its configuration. peculiar structure.

Why do giraffes have long necks?

The debate over why giraffes have such long necks is nothing new. On the contrary, centuries have passed since it began. One of the first to postulate ideas about this fact was the Frenchman Jean-Baptiste de Lamarck (1744-1829), who proposed that these animals previously had a short neck, but constantly stretched it to try to feed on the taller leaves of trees, developed this new phenotype, which was an acquired trait promoted by the environment and also heritable. However, Lamark’s ideas were discarded by the scientific community at the time.

Later, Charles Darwin (1809-1882) takes up Lamark’s evolutionary ideas and establishes that it was through a process known as a natural selection that this fact occurred. Darwin explains that giraffes with longer necks outlasted those with shorter necks, and could continue to feed when the lower leaves of the trees were exhausted and inherited this character from their descendants. This then explains the favouring of the long neck trait as an event of natural selection, linked to competition for food.

Although Darwin’s ideas, along with current scientific advances, have not been completely ruled out as to the fact that giraffes have long necks, other more recent hypotheses have also emerged. One is similarly linked to natural selection but in this case related to the sexual aspect. Accordingly, males in this group develop a duel known as necking, which consists of confronting each other using the neck as a weapon, so that they push and force each other, supporting one neck on the other. The male who wins this confrontation achieves reproductive success with the female, which could explain the favoured development, permanence and inheritance of the long neck trait in the group.

In view of the issues raised, there are positions that express the non-exclusion of both mechanisms mentioned above. In other words, the selection by food competition and the sexual aspect may have jointly originated and favoured the development of the giraffe’s long necks.

Although studies are still lacking to prove the evolutionary relationship, recent research [2] They coded the genetic sequence of giraffes and discovered the presence of genes that affect the skeletal and cardiovascular development of these animals. So, if they’ve undergone some small changes, it could explain why these mammals have become the tallest mammals in the terrestrial world.

Another proposed idea is that the giraffes that inhabit the hot African savannas are no better regulators of body heat than other animals in that habitat. Therefore, the neck may have evolved to favour this aspect, as, when directing it towards the sun, it manages to generate a shadow over the body itself, which allows reducing the solar incidence on it, thus regulating the temperature of its physical structure. In this sense, this hypothesis would be linked to an evolutionary aspect related to the animal’s thermoregulation.

 

Advantages and Disadvantages of Giraffes’ Long Necks

Undoubtedly, one of the biggest advantages of giraffes’ long necks is being able to feed on the leaves that are located in the highest parts of the trees, so this food is somehow unique to these animals. Another aspect that favours them is that being so tall, they can more easily detect the presence of predators in the area and be able to prepare to protect themselves. For example, in the presence of lions that are one of its main predators as adults.

Regarding the disadvantages, we can mention that their peculiar height characteristic makes them an animal easily identified from a distance, so their predators do not require much effort to find them. In this sense, its size makes it difficult to hide. Furthermore, giraffes require a highly efficient anatomical and physiological system to maintain themselves properly, which implies the need for a large amount of daily food and a great effort on the part of the body, especially in the environmental conditions in which they live.

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