Shape-Shifters - The Darwinian Tourist - page 16

they browse delicately along the branches of the sea fans, nibbling on the tiny
creatures trapped there.
These little equine fi sh show an uncanny resemblance to the branches of
the fans on which they live. The colors of their bodies and the little warts on
their skins help them mimic the details of the surfaces of the sea fan branches
with precision.
I found one of these seahorses, whitish with pink bumps, clinging in
a strong current to an actively feeding sea fan. Its pouch was swollen with
hundreds of tiny young, so it was clearly a male. The pregnancies of male
seahorses and pipefi sh provide one of the clearest cases in the natural world
in which the roles of the sexes are reversed. 2 The seahorse female, after giving
up her eggs to the male, has blithely left her progeny behind and moved on to
sexual pastures new. During her reproductive life she will compete fi ercely
with other females and attempt to mate with as many other males as pos-
sible, each of whom will serve as incubators for her of spring.
Seahorses are only a small sample of the fi sh diversity of Lembeh. Con-
sider the frogfi sh, which come in dramatic shades of red, white, pink, black,
and green. They nestle on the bottom, in the branches of corals, and among
the fronds of algae. Members of a single frogfi sh species can adopt dif erent
colors, depending on where they are trying to hide. They only reveal them-
selves when they open their mouths to suck in innocent fi sh. Frogfi sh have
such capacious mouths that they have occasionally been seen to eat other
frogfi sh almost as big as themselves.
In a clump of detritus lurked a spiny devilfi sh, which lived up to its
name—with its glaring eyes and its tooth-fi lled, downturned mouth it is the
stuf of nightmares. Its wing-like pectoral fi ns and the spines on its back are
covered with weeds and other growths that ef ectively conceal its outline. It
has evolved a surprisingly insect-like mode of locomotion, crawling forward
on appendages formed from parts of its pectoral fi ns.
Figure 8 ( opposite ) A pregnant male pygmy seahorse, Hippocampus bargobanti , at Lem-
beh Strait. The males nurse the babies while the females are free to seek other mates. This
seahorse was clinging to a fan coral in strong current, and in the background you can see the
actively feeding polyps of the coral.