Wednesday, 11 January 2017

Gorillas: nothing like King Kong!



Most people have two persistent images that they bring to mind when gorillas are mentioned. One is the fierce monster swatting planes at the top of the Empire State Building in the 1933 film King Kong; the other is the British naturalist David Attenborough being received hospitably by a family of gorillas in the Rwandan rain forest in his “Life on Earth” series broadcast in 1979.

So which image is closer to the truth? It should come as no surprise to learn that 1970s reality beats 1930s Hollywood every time! The gorilla’s reputation for ferocity is based on very shaky evidence.

The name “gorilla” goes back as far as 480 BC when a Carthaginian named Hanno used it for a human tribe that were noticeably hairy. It was applied to the animal only after 1847 when Thomas Savage, an American missionary working in West Africa, acquired a gorilla skull and heard stories about huge apes from local people. According to them, the skull would have belonged to “a monkey-like animal, remarkable for its size, ferocity and habits”. It would appear that he was treated to some fearsome stories about these creatures, which he had no reason to disbelieve although he never set eyes on a live gorilla himself.

Thus, when Thomas Savage took his gorilla skull back home and the newspapers got to hear about it, popular imagination was fired about the fierce creatures that terrorised the African jungle and were mercifully absent from the fauna of the United States. It was stories about African gorillas – read in childhood – that inspired the film producer Merian C Cooper to create a monster that he named “King Kong” and which only reinforced the public perception of what gorillas were like.

However, real gorillas are very different from King Kong! They are vegetarians that live on a diet of green plants and bark. They have huge stomachs to house the large intestinal tract needed to digest the enormous amounts of food that they need to eat each day, given that jungle grass is not particularly nutritious, and their large heads contain the powerful jaw muscles with which they have to chew their food for many hours every day.

That said, the food is plentiful and gorillas do not need to be in competition with each other for food supplies. A male “silverback” maintains a harem of females who occupy a relatively small territory in which they spend most of their time eating and sleeping.

It is, however, true that male gorillas will challenge each other when it comes to controlling harems of females. When a young male seeks to become “alpha” there will be a lot of posturing and noise from roaring and chest-drumming. However, there is usually little or any fighting, because the male who shouts louder and is physically larger will nearly always win the day by intimidation alone.

A visiting human is far more likely to be in danger if he or she is seen by a female gorilla to be a threat to her young, and that is true of most wild mammals.

Gorillas are gentle giants that deserve to be left in peace.

© John Welford 

Thursday, 5 January 2017

Sea snakes



Sea snakes are found in the Indian and Pacific Oceans and are of two quite distinct types. There are aquatic sea snakes and amphibious sea snakes. The former spend all their lives in the sea whereas the latter, which are also known as sea kraits, can come ashore; they have wide scales on their bellies that enable them to slither on land.

Aquatic sea snakes are viviparous, which means that they give birth to live young. Amphibious sea snakes lay eggs on land.

Sea snakes are reptiles, which means that they have to come to the surface to breathe, unlike fish. However, they are able to absorb a certain amount of oxygen from the water they swallow. They also have valves on their nostrils that close when they dive into deeper water.

Sea snakes feed on fish, eels and fish eggs. They are extremely venomous (their venom is ten times as deadly as that of most land snakes) and they use that venom to stun their prey before swallowing it whole.

The illustration is of a banded sea snake, which is one of the amphibious breeds.

© John Welford


Picture credit: Julie Bedford. Licensed under the Creative Commons Attribution 2.0 Generic licence.