Mike Dilger - Nature’s Babies

© Martin Harvey/NHPA

Baby elephants are never short of willing playmates.

By choosing a flightless lifestyle, the ostrich has been able to increase its size and weight to such an extent that it is now the world’s largest and heaviest bird. These features, together with their tremendous eyesight, phenomenal running speed and a vicious kick, enable them to protect themselves on the predator-riddled plains of eastern and southern Africa.

In the wild, ostriches are nomadic and will travel long distances in mixed-sex herds with other grazing animals such as zebra and antelope to track down the seeds, plant matter and odd insect which make up their diet. As ostriches lack teeth, they swallow stones to help grind up these tough foodstuffs in their gizzard. Although their wings are not used in flight, they are still large with a wingspan of over 2 m (6 ft 6 in), and male ostriches use them in elaborate mating displays when they compete for territory, social status and the all-important attentions of a small harem of females, or hens.

Once the dominant male has successfully fought off the competition, he will then mate with all of his females. This often leads to many of the hens laying their eggs in the same communal nest, resulting in the production of a clutch of over 30 eggs. Weighing in at 1.5kg (3 lb 5 oz) each, the world’s heaviest eggs are then incubated by the dominant hen and the male until they hatch after about 40 days. The father’s responsibilities do not stop there, as he then assumes sole control of the crèche, in order to both defend the hatchlings and also teach them what to feed on and how to find it.

Zebra

© Friu Polking/FLPA

Until they are able to fend for and defend themselves, ostrich chicks will always stick to safety in numbers.

Surely one of the most celebrated of all beasts among whale-watchers because of their ability to virtually leap clear of the water and their haunting songs, the humpbacks are also thought to carry out the longest migration of any mammal. Each year they will travel from their summer feeding areas in the higher latitudes to breed and give birth in tropical waters during the winter – a round trip of over 16,000 km (10,000 miles).

The humpback is found in all the major oceans and can reach an impressive 12 to 17 m (39 to 55 ft) in length. Their knobbly flippers are immensely long and can be used, together with the colour of the underside of the tail, to identify different individuals. Humpbacks only feed on krill and small shoaling fish in the summer, before living off their fat reserves during the breeding season. When feeding, they are capable of working cooperatively using a technique called ‘bubble-netting’: a number of whales will drive a shoal of fish into a tight cylinder of underwater bubbles, before piling in, mouth agape, to swallow – in just a few gulps! – thousands of fish filtered from the water by special baleen plates.

The male humpbacks are particularly vocal, and are capable of producing loud and complex ‘songs’ by forcing air through their nasal cavities. It is not understood if this is used by breeding males to try and intimidate other males or attract females, or even if it serves another function entirely. Groups of males will often compete for the females, and on their return to the tropics twelve months later, the females will give birth to a 5 m (16 ft) long, 700kg (1,500 lb) calf. The young calf will then be a constant shadow beside its mother until weaned a year later.

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