Tuesday, August 21, 2012
Do Giraffes mourn their dead ones?
A curious incident of a deceased giraffe has reopened the question of whether animals mourn their dead.
Zoologists have witnessed a giraffe mother investigating and refusing to leave the body of her dead calf, the third such incident on record.
Other social animals such as elephants and chimpanzees are known to investigate their dead, especially the bodies of their close relatives.
Such behaviour raises the prospect that animals have a "mental model" of death.
Details of the latest incident are published in the African Journal of Ecology.
Zoologist Professor Fred Bercovitch studies on behalf of the Primate Research Institute and Wildlife Research Centre at Kyoto University, Japan and the Giraffe Conservation Foundation, based in Purley, Surrey, UK.
While tracking Thornicroft's giraffes in the South Luangwa National Park, Zambia, Prof Bercovitch witnessed a female giraffe splay her legs and bend down to her newborn, but dead calf.
She spent several minutes licking the calf, before standing upright. She then repeated the behaviour a few times, spending more than two hours in total investigating the body of her lost offspring.
The behaviour is striking for a number of reasons.
Females giraffes rarely spend any time alone, yet this individual spent hours with her dead calf away from other females.
Giraffes rarely splay their legs to bend down, apart from when to drink or feed.
And apart from two other similar incidences, giraffes have not been seen intensively investigating their dead.Gradient of loss
"The maternal reaction to her dead offspring was not as prolonged as that shown by African elephants," Prof Bercovitch writes in the journal.
Elephants and chimpanzees, which both live in highly social groups, have been seen apparently mourning the loss of their kind.
Elephants become agitated when a member of the herd dies, investigate dead conspecifics and often guard the bodies.
Chimps and snub-nosed monkeys have been recorded carrying dead offspring, often carrying older babies for longer.
But it is worth noting, Prof Bercovitch says, that there also appears to be a gradient in the way giraffes react to their dead.
Of the three incidents so far recorded, one female giraffe spent four days alongside the dead body of her older calf.
That took place in 2010 in the Soysambu Conservancy in Kenya, dubbed "The curious incident of the giraffe in the night."
There, biologist Zoe Muller observed a Rothschild's giraffe stand guard over her one month old calf that had just died. Seventeen other female giraffes surrounded the body at various times during the four days.
In the incident in Zambia, witnessed late last year by Prof Bercovitch, the Thornicroft's giraffe spent two hours with her apparently stillborn offspring.
The final incident occurred in 2011, when a herd of Namibian giraffes stopped to inspect a site where a young female giraffe had died three weeks earlier. A male giraffe stopped walking, splayed his legs and sniffed at the ground. Four other herd members investigated the site in the same way.
However, while the behaviour of elephants and primates has been used to suggest that some mammals are capable of conceptualising death, Prof Bercovitch remains cautious.
The incidents clearly show that giraffe mothers bond with their calves in a more pronounced way than realised, he says.
But the importance of the discovery may also lie more in that it widens the number of species that react when relatives or members of their own kind die.
Only by collecting evidence from a range of species can scientists begin to investigate whether animals do mourn, and when in evolution the trait appeared.