2. 5
metric tons
weight of adult
male african
forest elephant
6
metric tons
weight of adult
male african
savanna elephant
5. 4
metric tons
weight of adult
male asian
elephant
Female chimps
play with dolls
Youngsters mimic mothering
by treating sticks as babies
By Bruce Bower
Deep in a Ugandan forest, Betsy Wetsy
has gone wild. Young females in one African chimpanzee group use sticks as dolls
more than males do, often treating pieces
of wood the way a mother chimp would
care for an infant, a new study finds.
The ape observations, collected over
14 years of fieldwork with the Kanyawara
chimp community in Kibale National
Park, provide the first evidence of a wild
nonhuman animal exhibiting sex differ-
ences in play, two primatologists report in
the Dec. 21 Current Biology. This finding
supports a controversial view that biology
as well as society underlies human boys’
and girls’ contrasting toy preferences.
A young chimp cradles a piece of bark.
In one group, females used objects as
dolls more frequently than males did.
way back in our evolutionary lineage
and predate socialization in human
cultures,” says Elizabeth Lonsdorf,
director of the Lester E. Fisher Center
for the Study and Conservation of Apes
at Lincoln Park Zoo in Chicago.
African elephants are two species
forest and savanna dwellers prove distinct in gene analysis
By Tina Hesman Saey
Forest-dwelling African
elephants are a separate
species from Africa’s
savanna elephants, a
genetic analysis shows.
The research, published
December 21 in PLoS
Biology, “does a very
thorough job of nailing shut the coffin on
some of the more heretical theories”
about elephant evolution, says Stephen
O’Brien, a geneticist at the National Cancer Institute in Frederick, Md., who was
not involved in the research.
Forest and savanna elephants evolved
into different species from a common
ancestor between 2. 6 million and 5. 6 million years ago, the new analysis reveals.
A study shows that Africa’s forest (left) and savanna
elephants (right) are two species. Forest elephants are
smaller, with more rounded ears and straighter tusks.
In the study, researchers compared
nuclear DNA from living elephants as
well as from a 43,000-year-old woolly
mammoth bone from Siberia and from
a 50,000- to 130,000-year-old North
American mastodon tooth. The African
forest and savanna groups are at least as
different as Asian elephants and mammoths, the researchers say.
“I’ve always argued that they are
very different, but that level of
difference surprised me,” says study
coauthor Alfred Roca, a conservation
geneticist at the University of Illinois at
Urbana-Champaign.
People have debated for a long time
whether the big savanna elephants and
smaller forest elephants belong to one
or two species. “This has been an ongoing debate since before genetics began,”
Roca says.
The t wo pachyderms look different but
sometimes come together and breed, producing hybrids. Hybrid males are sterile,
but females can breed.
The study may not be the final word on
the number of elephant species, but many
researchers say it is convincing. “It’s hard
not to agree with this overwhelming
amount of genetic data that gives such
clear-cut answers,” comments Sergios-Orestis Kolokotronis, a conservation
geneticist at the American Museum of
Natural History in New York City.
clockwise from top: suzi eszterhas; a. schaefer; Nicholas GeorGiadis
www.sciencenews.org
