Together they are strong: Similar to us humans, life in a group increases the chances of survival for female giraffes. This is now confirmed by a study with wild giraffes in Tanzania. Accordingly, the female giraffes who team up with conspecifics and look for food together and raise their young live longer. The benefits of group living have an even greater impact on animal survival than their habitat or proximity to human settlements.
Not only humans are considered social beings – primates such as chimpanzees and gorillas also live in larger groups and have social ties. Marine animals such as dolphins, whales and sharks also form complex social structures and work together. And even birds like thieving magpies support their fellow species. This is because the individuals in the community often have a greater chance of survival.
What about giraffes?
Researchers working with Monica Bond from the University of Zurich (UZH) investigated in a long-term study whether female giraffes also benefit from their social behavior and life in groups. They also wanted to find out whether social behavior has a greater impact on the giraffes’ chances of survival than the natural environment and humans as a possible disruptive factor. For five years, the team documented the social behavior of more than 500 wild Maasai female giraffes (Giraffa camelopardalis tippelskirchi) in Tanzania, who lived together in several social communities, each with around 60 to 90 adult females. With the help of algorithms for analyzing the animal groups, the researchers examined the individual and collective influences on the survival of the animals.
It turned out that giraffes actually survived longer in larger groups of around 50 animals than socially isolated females. The researchers observed that the giraffes repeatedly reunited to form other groups over the course of a day. In doing so, however, they maintained specific friendships over a long period of time. “Living with a larger number of females is associated with an increased survival rate of female giraffes, even if they change groups frequently,” explains Bond. “The sociability of the animals is more important than environmental factors such as the vegetation or the proximity to human settlements,” adds the researcher. It is true that female giraffes who lived near cities apparently had a somewhat lower survival rate due to poaching. However, the main causes of animal mortality were socially influenced factors such as illness, stress or malnutrition.
For foraging, protection and cooperation
But how exactly does social contact reduce this risk of survival? “Social relationships can improve the efficiency of foraging,” explains Bond’s colleague Barbara König. To this end, female giraffes will probably team up with an optimal number of at least three other females in order to exchange information about the best sources of food. In addition, the union with other females helps to cope with the competition with conspecifics, imminent danger from predators, disease risks and psychosocial stress, König continues. Other advantages of group life can be that the females are less bothered by males ready to mate, that they look after and protect their young together, or that the presence of familiar females reduces stress.
The following applies: the more bonds they have with other females, the less stress and competition they feel and the higher their chances of survival. “Female giraffes seem to have an advantage in networking with several other females and thus develop a feeling for a larger community, but not for a single small group,” summarizes Bond. Similar social habits also occur in various species of monkeys such as rhesus monkeys (Macaca mulatta) and diademed monkeys (Cercopithecus)
mitis stuhlmanni).
Source: University of Zurich, Article: Proceedings of the Royal Society B: Biological Sciences, doi: 10.1098 / rspb.2020.2770