When it comes to giraffes, can you spot the difference? A new study
reveals there's more to the animals' species diversity than once suspected.
The study researchers collected and analyzed DNA from skin samples
representing 190 giraffes from across Africa, the first such analysis to
include data from all nine formerly accepted subspecies.
The results showed that what was long thought to be one giraffe species
is in fact four species. [All in the Family: Giraffes Are 4 Species (Photos)]
The 18th-century naturalist Carolus Linnaeus provided the first
scientific description of a giraffe in "Systema Naturae" in 1758,
using a Nubian giraffe — one of the now-defunct subspecies — as a model.
However, Linnaeus had never actually seen a living giraffe, and described it
based on reports that were 200 years old, according to the authors of the new
study.
Over time, more giraffe subspecies were identified. The nine recognized
subspecies were described between 1758 and 1911, and inhabited 12 African
countries, including South Sudan, Ethiopia, Kenya, Somalia, Uganda, South
Africa and Zimbabwe.
Subspecies designation was based on differences such as the shapes of the
ossicones — the animals' knobby "horns" — along with variation in
patterns on the giraffes' coats and differences in where they lived. But these
distinctions were unreliable, the study authors wrote. Giraffes haven't been
studied as closely as other large African mammals such as lions, elephants and
gorillas, the researchers explained in a statement, and much about the
long-necked animals remains unknown.
Giraffe's genetic complexity in particular has been "underestimated,"
the scientists said in the study, and greater attention was required to define
giraffes' relationships and diversity.
A tall
order
The researchers spent five years assembling and testing genetic material
from giraffes ranging across Africa. When the dust settled, four species were standing tall: the southern giraffe (Giraffa
giraffa), northern giraffe (G. camelopardalis), reticulated giraffe
(G. reticulata) and Masai giraffe (G. tippelskirchi).
The nine subspecies were absorbed into these four newly defined species,
with the Nubian giraffe — the first representative, from more than 300 years
ago — now identified as a subspecies of northern giraffe.
Recognizing four distinct giraffe speciesshould be a game
changer for conservation plans, the researchers said in the study.
Fewer than 100,000 giraffes remain in the wild, down from an estimated
150,000 that roamed the savannas 30 years ago. And because the species don't
interbreed, population numbers for all African giraffes won't accurately
represent whether each group is doing well. Using this new information about
giraffe genetics, governments and biologists can create more focused efforts to
ensure that all four species will be neck and neck in their race toward future
success, the scientists said.
The findings were published online in the journal Current Biology.




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