At 6:00 in the morning on December 14, 2004, an Aldabra giant tortoise (Dipsochelys dussumieri), the Indian Ocean’s analogue to the oversized tortoises of the Galápagos, ambled out of the sea at Kimbiji, 22 miles south of Dar es Salaam in Tanzania. Inspection of the tortoise’s shell showed faint concentric growth rings, indicating that the animal came from the native population on Aldabra, where the high density of tortoises leads to slow growth, rather than from introduced populations elsewhere in the Seychelles or on Changuu Island near Zanzibar. Aldabra also made sense as the point of origin based on the direction of prevailing currents. A trip from Aldabra to Kimbiji would cross 460 miles of ocean waters as the crow flies, and presumably somewhat farther as the tortoise floats.

The Kimbiji tortoise was emaciated, as one might expect, but even more telling was the fact that its front legs and part of its lower shell were covered with thickets of goose barnacles, like the hull of a boat. Barnacles settle as tiny larvae and, once fixed, do not move. From the size of the largest ones, it was surmised that the tortoise had been in the ocean for at least six weeks.

I.4 The Kimbiji tortoise. Photo by Catharine Joynson-Hicks.