Page 51 - BBC Wildlife Volume 36 #04

GHARIALS

Far left: India’s With their mothers keeping the sandbanks clear of
Chambal River intruders for two months, the embryos develop in the
has sandbanks, underground incubation chambers. As spring gives way
which gharials to summer, the heat builds up. The sand temperature
use as nest sites.
Left: the long, assigns the sex of the hatchlings, since crocodilians have
narrow snout no sex chromosomes. At the height of summer, when
enables the daytime temperatures touch an infernal 45–50ºC, the
crocodilian to young are ready to hatch. They can’t dig themselves out
whip its head
sideways to of the 45cm-deep hole, though. From inside their eggs
snatch fish. they call for help – sounds the expectant mothers have
been waiting to hear. How each mother knows where her
nest is located remains a mystery.

WARM WELCOME
After nightfall, the devoted mothers heave themselves out
of the water once again. In the heat the river has receded
farther from the bank, yet they hike up the towering
sandbanks–almost in unison, since all the nests hatch
Below: the simultaneously. In other crocodilian species, the mothers
gharial’s nose helptheir babies hatchby rolling theeggsintheir mouths
contain sensory and squeezing gently. The long narrow gharial snout doesn’t
cells that can
detect vibrations
det ect vibr a allow this. So the females simply open the nest and let the
made bypre young hatch on their own.
ey
in the water r. The freed hatchlings scurry and slide to the water to their

DESPITE THEIR ENORMOUS SIZE,

GHARIALS HAVE NO INTEREST IN
EATING BIRDS OR MAMMALS.

THEIR TEETH HAVE EVOLVED
TO GRAB SLIPPERY FISH.