Richard Collins: How herds of elephants cope with newborns and their mothers

Researchers from Oxford University have succeeded in discovering how an elephant herd cares for vulnerable members

Led by a matriarch, there are typically about ten members in a herd of elephants.

The African elephant is the largest land animal alive today. Being very big has its advantages; predators, such as lions, can’t challenge you and there is improved heat retention. Large objects take longer to cool down when temperatures drop so big creatures fare better than small ones in adverse weather.

But there is a downside to being jumbo-sized; more food is needed to fuel a huge body. An adult bull may consume up to 170kg of vegetation in a day. He spends most of his time on his own, so there should be sufficient resources fairly locally to sustain him. Female elephants do things differently. They live in herds, with young males and calves. Led by a matriarch, there are typically about ten members. Obtaining food and water for such a large troop can be challenging; resources in the vicinity soon become exhausted. The herd must, therefore, keep moving on to fresh pastures.

Predators are on the prowl, watching for an opportunity to strike, but babies are relatively safe in herds. Mothers and other females, especially aunties, watch out for them, coming to the rescue of a youngster having difficulty in swamps or rough terrain. A calf must keep up with the herd at all costs.

Synchronising births might help. If all mothers had calves at the same time, only one prolonged stop would be necessary. Elephants, however, don’t opt for this; they breed randomly throughout the year and youngsters may be present in herds at any time. So how do newly-born infants and their mothers cope? Do herds slow down to help small babies keep up?

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Researchers from Oxford University have succeeded in answering these questions. They fitted GPS collars to 23 pregnant elephants in Northern Kenya and tracked their movements.

A newly-born calf is on its feet within minutes and able to walk. Both mother and baby, the tracking data showed, are mobile immediately and move with the herd. They are able to keep up, the researchers found, ‘except for a small dip in speed on the day of the birth itself. In fact, the speed on the day before the elephant gave birth and the day after (i.e. the first complete day of the calf’s life) were not different from the yearly average speed’, says lead author Lucy Taylor. Herds, therefore, don’t need to slow down to help youngsters.

The results suggest a solution to an even greater problem. Elephants have a 22-month gestation period, the longest of any mammal. Why? A blue whale, the largest animal ever to have lived, may be up to 25 times heavier than an African elephant, but its pregnancy takes just 12 months.

The elephant gestation period, the researchers suggest, enables the baby to develop sufficiently in the womb to be able to walk with its mother immediately after being born. The extended pregnancy evolved as a transport and security mechanism. Babies are safe inside their mothers until they are able to travel safely, with the herd, under their own steam. The prolonged pregnancy ‘may have evolved to help elephant herds stay together’, the researchers suggest.

• Lucy Taylor et al. Movement behaviour after birth demonstrates precocial abilities of African savanna elephant calves. Animal Behaviour. 2022.