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Sabertooths strong-armed victims
By Gwyneth Dickey
A saber-toothed cat’s pounce
may have been as bad as its
bite. These extinct animals
had exceptionally strong
forelimbs that probably held
a victim still while razorlike
teeth ripped out its throat, a
new study shows.
Most carnivorous cats
suffocate their victims with
a crushing bite to the throat
or nose. This wouldn’t have worked for
sabertooths because their formidable
twin canines were surprisingly fragile.
The teeth were oval-shaped when cross-sectioned, not round like other cats’,
making the canines good for slicing flesh
but easily snapped by writhing prey.
A new fossil analysis shows how one
saber-toothed cat, Smilodon fatalis,
Saber-toothed cats (skull and skeleton shown) may
have pinned their prey with strong forelimbs.
avoided breaking those pearly whites. Its
humerus, the forelimb bone between the
shoulder and elbow, was stronger than
that in any other cat, living or extinct.
“This is the first study to look at the
internal bone to see how strong limbs
are and how they resist forces,” says Julie
Meachen-Samuels, who did the work at
UCLA and is now at the National Evolu-
tionary Synthesis Center in Durham, N. C.
Evolution 2010, Portland, Ore.,
June 25 – 29
Fishy odor just like dad’s
a tendency for daughters to fall for a
guy like dad helps keep neighboring
species of fish from interbreeding.
Two distinct species of the three-
spined stickleback dart about
in each of several lakes in British
columbia. The open-water, slimmer
ones mate with their own kind, and
the larger, bottom-feeding ones mate
with theirs. experiments in which
researchers switched egg clutches
between the species now show that,
early in life, females of both kinds
pick up some cue from their fathers,
which do the child care in the stickle-
backs. Switched daughters grew up
to prefer their foster father’s species,
while daughters raised with no father
around showed no species preference in
mating. Further tests suggest that one
cue was dad’s odor, Genevieve Kozak
of the university of Wisconsin–Madison
reported June 26. a process known as
imprinting may help the stickleback spe-
cies stay separate despite the close quar-
ters. The work may shed light on other
cases in which species form and stay
separate while sharing space, such as in
african cichlid fish. — Susan Milius
Adaptation breeds confusion
The recent evolution of camouflage
among lizards in the dunes of White
Sands national Monument in new
Mexico can lead to misunderstanding
when males choose to make love, not
war. Since the dunes developed, a light-
colored form of the normally dark-shaded
eastern fence lizard has arisen; the new
form blends in with the landscape.
