THE STEINHART AQUARIUM - Gulf of Guinea Science ...

206 A Docent Field Guide to the Species of the Steinhart Aquarium
is swallowed whole.
Reproduction: Male attracts a mate by repeatedly
extending the head toward the female and
opening and closing its mouth. Fertilization
internal. Female lays 12–28 ping-pong ball
sized brittle-shelled eggs terrestrially. The eggs
hatch about 200 days after being laid.
Mortality/Longevity: Life span: up to 15 yrs.
in captivity.
Conservation Status: Reported to be locally
common.
Remarks: South American Indian name
“matamata” translates as “I kill.”
A poor swimmer; its legs are adapted for
walking over bottom of habitat.
Has been described as most resembling a pile
of debris. Slow movement, mottled colors, and
algal coating all combine to create the illusion.
Alligator Snapping Turtle
Macrochelys temmincki (Chelydridae)
Snapping Turtles
Distribution: Southeastern United States and
Central America.
Habitat: Primarily quiet, muddy freshwater,
rivers, streams, lakes and ponds; leaves water
only to deposit eggs. Juveniles occasionally
near bottom of small mud and gravel streams,
to 9–29 cm deep.
Appearance: Big head, long tail. Three ridge
keels on the broad carapace rise to knobby
keels. Length to 80 cm, weight to 113 kg. Males
have been known to exceed 100 kg; females are
much smaller. The largest individual turtle in
the exhibit is over 55 kgs. The rest are likely
~45 kg.
Diet: Lie-in-wait predator. Rests on substrate
with its mouth open and lures fish to its mouth
with a movable, pink wormlike tongue appendage.
Also takes crayfish, crabs, snails,
freshwater mussels, salamanders, snakes, very
small alligators, small mammals, water birds,
briar roots, wild grapes, acorns, and scavenges
as well. At the Steinhart, are fed fish, including
herring and tilapia. Because they are accustomed
to being feed regularly, they are rarely
tempted by their tankmate fish.
Reproduction and Development: Male climbs
onto the female’s carapace from behind. As in
all reptiles, fertilization is internal. Female’s
terrestrial nest is typically within 72 m. of wa-
ter. A single clutch of 9–61 eggs (35 average) is
laid per year. Larger females produce larger
clutches. Incubation lasts 79–113 days, depending
on temperature. Warm and low incubation
temperatures result in all female neonates.
Intermediate incubation temperatures produce
mostly males.
Mortality/Longevity: Life span: to 100 yrs. (A
second source suggests 150 yrs) Eggs preyed
upon by raccoons, river otters and wading
birds. Humans collect adults for food.
Conservation Status: Listed as Threatened
on the IUCN Red List. CITES Appendix III.
Still harvested as the key ingredient of turtle
soup. Habitat degradation also threatens them.
Hatchlings produced for the pet trade.
Remarks: This is the largest freshwater turtle
in North America.
Can swim, but most locomotion is by bottomwalking.
Can remain submerged for about an hour.
Despite its reputation, the species does not readily
bite; however, its powerful jaws and sharp
beak can easily sever a finger, bone and all.
Some living Steinhart specimens were
“rescued” in 1972 from a “turtle soup” fate
from a restaurant in San Bruno. A few months
earlier than the arrival of their shipment by air,
the California Fish and Game Commission had
adopted regulations restricting snapping turtle
importation, a law that remains on the books,
and so they were confiscated and ultimately
released to the Steinhart. Our middle-aged,
lucky survivors are thought to be at least
~40–50 years old.
Arrau River Turtle aka South American River
Turtle
Podocnemis expansa (Pelomedusidae)
Afro-American Side-necked Turtles
Distribution: Northern South America:
Amazon, Negro and Orinoco River basins.
Habitat: Freshwater; large rivers and their
tributaries, lagoons and forest ponds. Restricted
to calm waters of large rivers during the dry
season, but move into the flooded forest where
food is plentiful during the high-water season.
Appearance: Max. size: 100 cm. Carapace
broad, flat; wider in the back than the front.
Males smaller than females, which can weigh
up to 90 kg.