THE STEINHART AQUARIUM - Gulf of Guinea Science ...

Diet: Aquatic vegetation and fruit, also insects
and sponges. Eats during the rainy season
when the forest is flooded; fasts during dry
season. In captivity, feeds on a vegetarian/fruit
diet with a bit of fish added.
Reproduction: During the dry season, migrate
to nesting sites on beaches. Females dig a
nest in which they lay 50–150 spherical eggs,
and then cover them with sand. After about
45 days, hatchlings emerge, usually at night
or early morning to avoid midday heat and
predators, and head directly to water. Colonial
nesting and simultaneous hatching helps
maximize survival numbers of this perilous
journey. Hatchlings’ carapace is quite small,
about 5 cm long.
Mortality/Longevity: Recent studies on
the growth patterns of bones and carapace
suggest these turtles can live up to 50 years.
Though young are vulnerable to predation,
the massive size of adults protects them from
most predators except man.
Conservation Status: U.S. Fish and Wildlife
Service: Endangered; IUCN: Endangered;
Lower risk, conservation dependent. Eggs
and adults have been overcollected for food.
These turtles are considered rare throughout
the Amazon.
Remarks: A fossil Pelomdusid is thought to
be the largest freshwater turtle to have ever
lived (carapace length: 230 cm). Even today, the
Arrau is one of the largest freshwater turtles
in the world.
Sidenecked turtles have a long neck which
can be withdrawn horizontally within the
shell, leaving it partly exposed, rather than
retracting it in a vertical ‘S’ bend as in most
other turtles.
Our handsome “fellow” (sex unknown) is on
loan from the San Francisco Zoo during the
renovation of their Tropical Building.
Weight: 20 kg. Age: unknown.
“Art,” as we call our turtle, was confiscated in
Miami and came to the SF Zoo via the Miami
Metro Zoo in 1997.
Radiated Tortoise
Astrochelys radiata (Testudinidae)
Distribution: Occur naturally only in the
extreme southern and southwestern part of
Madagascar.
California Academy of Sciences
207
Habitat: They prefer dry regions of brush,
thorn and woodlands.
Appearance: The basic “tortoise” body shape:
high-domed carapace, a blunt head, and
elephantine feet. Legs, feet and head are yellow
except for a black patch on top of the head.
Carapace is brilliantly marked with yellow
lines radiating from the center of each dark
plate of the shell, creating a star pattern.
Diet: Grazing herbivores, they also eat fruits
and succulent plants. A favorite food in the
wild is the Opuntia cactus.
Reproduction and Development: The male
begins this fairly noisy procedure by bobbing
his head and smelling the female’s hind legs
and cloaca. He mounts her from the rear,
hissing and grunting, while striking the anal
region of his plastron against the female’s
carapace. Females lay from 3–12 eggs in a
pre-excavated hole about 15 cm deep and then
depart. Incubation is between 5–8 months;
juveniles are between 3–4 cm upon hatching
and soon after attain the high-domed carapace.
They can grow to a carapace length of up to 40
cm and weigh up to 16 kg.
Mortality/Longevity: Radiated tortoises may
live as long as 40–50 years.
Conservation Status: Critically endangered in
the wild due to loss of habitat, being poached
for food, and being over exploited in the pet
trade.
A team of biologists from the Turtle Survival
Alliance predicts that unless drastic
conservation measures take place, the
species will be driven to extinction within
the next 20 years. Conservation efforts:
habitat preservation, environmental education
programs, and captive breeding. A. radiata
is included in the Species Survival Plan of
the worldwide Association of Zoos and
Aquariums.
Remarks: These cold-blooded reptiles move
from place to place to moderate their body heat
and are active after rain. Traditional cultures
revere the tortoise (it brings rain; when there
are no more animals, there will be no more
rain).
Like other tortoises their shell is supplied with
blood vessels and nerves, which enables it to
sense when being touched.
In some areas of China, a radiated tortoise