Huge Clutch of Eggs Excavated

This week at our Southern California Conservation Center we uncovered a huge clutch of eggs laid by one of our old female Burmese Black Mountain Tortoises (Manouria emys phayrei). These eggs are quite large, soft and round (think Leatherback Sea Turtle eggs). The total egg count from this nest was 62! The largest nest on record for this species is 68 eggs. The Burmese Black Mountain Tortoise is the largest tortoise in mainland Asia. This is a forest tortoise, dwelling under full tree canopy at elevations of 3,000 ft.

The following snippet was taken from "Forest Tortoises in the Mist."  The Tortoise. Volume 1 Number 1. Craig B. Stanford, Pratyaporn Wanchai, and Kumthorn Thirakupt

When you think of a tortoise, you probably have a vision of a behemoth plodding across a volcanic mountain in the Galapagos Islands, or perhaps a smaller version in the deserts of the American southwest. But a few species still live in the tropical forests, where we believe the first tortoises evolved. Among the diverse wildlife of this rain forest lives the Asian Forest Tortoise (Manouria emys), or Tao Hoq. In Thai, its name means “six-legged” because of the large spurs protruding from under the shell on either side of its tail. Many Thai believe the spurs help propel the animals up the sheer mountainsides they inhabit, a notion that we had always considered quaint until we saw the tortoises in action. A second member of the genus Manouria, the beautiful Impressed Tortoise (Manouria impressa), lives in hilly forests across Southeast Asia as well.

In any language, the Asian Forest Tortoise is an impressive animal. It is one of the largest tortoise species in the world today, trailing only the giants of the Galapagos Islands and Aldabra Atoll and the African Spurred Tortoise (Centrochelys sulcata) of the Saharan regions of Africa. The species lives mainly in densely forested mountainous terrain, from the easternmost Indian subcontinent across Myanmar and southward through Thailand and Malaysia. Or at least it used to. These days Asian Forest Tortoises are confined to a few remaining forest tracts in the proper habitat, where human disturbance is not too great. Humans have wrought nothing but death and destruction at an ever-increasing pace, when it comes to all of the world’s three hundred chelonian species.

The Asian Forest Tortoise consists of two distinct subspecies. The southern subspecies, Manouria emys emys, occurs in peninsular Malaysia and through parts of the Indonesian archipelago. The northern subspecies, M. e. phayrei, is larger, darker in color, and occurs in hilly regions from Myanmar (it is almost certainly extirpated in India and Bangladesh) through southern Thailand. A good-sized adult M. e. phayrei can reach sixty centimeters in length and weigh some twenty kilograms.

The genus Manouria is believed to be among the most primitive of all tortoises. The Impressed Tortoise and the giant Asian Forest Tortoise displays traits we don’t usually associate with tortoises. Consider, for instance, their rain forest life. Instead of basking in the sun of a tropical isle or desert, the Tao Hoq is more likely to be found sitting in muddy thickets. It’s not uncommon to come across one of these giants sitting in the middle of a cool clear stream, with only its head held out of the water. Or consider its diet, which prominently features bamboo shoots and mushrooms. Indeed, the closely related Impressed Tortoise appears to be the only reptile in the world that features mushrooms centrally in its natural diet.

When it comes to social behavior and reproduction, the genus Manouria is eccentric too. Many tortoise species have distinctive mating calls, from grunts and groans to chirps. But Dr. James O. Juvik of the University of Hawaii-Hilo has recorded the low-frequency sounds made by members of this genus, which sound a lot like growling as they jostle among themselves in captivity.

The genus Manouria’s nesting habits are also very un-tortoise-like. Females of both species use their front and hind legs to gather together a meter-high mound of debris from the forest floor, building a nest mound not unlike that made by alligators. The female then climbs atop the mound and deposits a clutch (up to fifty eggs for M. emys, only a dozen for M. impressa) deep inside. For days after egg-laying, the mother will sit on the nest, chasing intruders away. Breeders and zookeepers have reported nest-guarding females attacking everything from other tortoises to dogs and people in an effort to protect their precious clutch.