Old animals face many problems, and some animals cannot do without the help of relatives. The authors of the new study found that the world's largest flying birds - wandering albatrosses - take care of their old mates, leaving them less hungry during the incubation period.
Albatrosses can spend about two weeks gathering food on the high seas.
In addition to being known as the longest-winged bird in the world, the wandering albatross is also known for its lifespan, which can last up to 50 years. By choosing one mate throughout their lives, they mate on average every two years and breed on remote islands where they don't have to worry about land predators.
However, laying eggs is not an easy task for a couple: for two and a half months, one partner must stay in the nest while the other partner searches for food in the sea. In order to collect enough fish, molluscs and crustaceans, the albatross leaves the nest for an average of 12 days without food for the second bird.
By studying the behavior of 71 pairs of albatrosses nesting on the Cross Islands in the South Indian Ocean, researchers at the University of Liverpool (UK) found that time spent at sea with older partners was less than with younger partners. Scientists believe that because older albatrosses have a harder time enduring long periods of hunger, their partners assess the risks and prefer to spend less time gathering food to avoid losing the pair.
While this behavior may seem completely altruistic, both birds actually benefit from it. Feeding an albatross cub is not easy: the voracious baby requires about 100 kilograms of food to "raise", and during this time someone has to keep it warm and protect it from other albatross. A single parent who has received goiter rejection but has lost a partner is clearly unable to complete such a task.
Therefore, the albatross must become cautious for its own sake. It is likely that it is this sensitivity to a mate's needs that allows birds to successfully nurse their young into old age.
The research was published in the journal Ecology and Evolution.
