A

rriving on the island of Timor more than

40,000 years ago, the irst inhabitants would

have been confronted with an astounding sight:

rats the size of cats and small dogs scurrying

through the trees and undergrowth of the

forests. Rather than being frightened, however, these early

inhabitants must have been delighted at the delicious bounty

on offer. Archaeological excavations throughout Timor-Leste,

which preserve the records of what people ate and how they

lived for forty millennia, has unearthed thousands of chewed,

cut and burnt bones of giant rats. It’s clear people were hunting

and trapping these rats for food, cooking them over open ires,

and discarding their chewed remains on the cave loors.

The island of Timor is situated at the eastern end of a region

known as Wallacea, which consists of more than 17,000 islands

that have never been connected to either the South-East Asian

or Australian continents (Fig. 1). Many of the plants, fungi

and animals that call these islands home must have travelled

across the seas at some point to get there.

Sea crossings are not easy for terrestrial organisms, which require

access to nutrients and fresh water in order to survive. Any species

newly arriving on an island are faced with novel ecosystems, as

each island is a unique blend of the species that were able to get

there. And, once on the island, reproductive choices can be quite

limited: most islands have limited resources that can only support

small populations of species that are usually descended from an

even smaller number of colonising individuals.

Because of this, weird things can happen to organisms that

manage to reach and colonise isolated oceanic islands, partic-

ularly mammals. Large species like elephants and hippopota-

muses shrink down in size, some to no more than 200 kg, or

about 2% the size of their ancestors. On the lipside, tradi-

24 | APRIL 2016

The Giant Rats

of Timor

JULIEN LOUYS

Giant rats coexisted with humans for 40,000 years on the island of Timor. Their extinction is

a cautionary tale about the ecological consequences of deforestation in South-East Asia today.

Figure 1. The location of the archaeological sites on the island of Timor in Wallacea.

Figure 2. Giant rat

skull next to a modern

black rat. Credit: CSIRO

Map courtesy of S. Kealy