Galapagos Rodents

Category: Rodents
Family: Muridae

Endemic Species: Large Fernandina Rice Rat, Santa Fe Rice Rat, Santiago Rice Rat and the Small Fernandina Rice Rat

Before the arrival of man, the only species of rodent to occur in Galapagos were the rice rats. There were formerly seven species, all endemic to the archipelago, but the introduction of the ubiquitous Ship Rat is believed to have led to the extinction of three of these species. Rodents are small to medium-sized furry mammals with long scaly tails, pointed faces and short, round ears.

LARGE FERNANDINA RICE RAT

Scientific Name: Nesoryzomys narboroughii
Family: Muridae
Length: Up to 35 cm (14 in)

Locally common throughout the island, particularly in the arid zone. Confined to Fernandina Island. Little is known about the biology or ecology of this species, although it is believed to breed principally during the warm/ wet season.

Identification:Considerably larger than the Small Fernandina Rice Rat, from which it is distinguished by its paler, grayish-black fur with pale underparts, and white feet. The tail is about the same length as the head and body.

Behavior: Active at night and therefore rarely seen by visitors during a Galapagos cruise; feeds on the ground.

SANTA FE RICE RAT

Scientific Name: Oryzomys bauri
Family: Muridae
Length: Up to 20 cm (7.8 in)

Locally common, particularly in the arid zone. Confined to Santa Fe Island, where it is free from the depredations of Black Rat. Breeding rakes place during the warm / wet season.

Identification: The Santa Fe Rice Rat is a small, brown rat with a pointed nose; long legs; long, pale but black-soled hind feet; and pale underparrs. They have large, rather bulging eyes and the ears are large and sparsely-haired. The tail is about the same length as the head and body, and is slender and naked.

Behavior: Unafraid of humans but active principally at night and therefore rarely seen by visitors. When active, they spend their time on the ground.

SANTIAGO RICE RAT

Scientific Name: Nesoryzomys swarthi
Family: Muridae
Length: Up to 35 cm (14 in)

Only rediscovered on Santiago Island in 1997, having not been recorded since 1906. Locally common in the arid zone to the north of the island. Although nothing is yet known about its biology or ecology this is the only species of rice rat which is known to have been able to compete successfully with the introduced Black Rat.

Identification: Similar in size and structure to the Large Fernandina Rice Rat. The fur is dark brown, although the underparts are pale and the feet are white. The tail is about the same length as the head and body.

Behavior: Nocturnal.

SMALL FERNANDINA RICE RAT

Scientific Name: Nesoryzomys fernandinae
Family: Muridae
Length: Up to 22 cm (8 in)

Only recently described, having been recorded only from owl pellets until 1995 when the first live animals were trapped. Confined to Fernandina Island. Probably locally common, particularly at higher elevations, although nothing is yet known about its biology or ecology.

Identification: Considerably smaller than the Large Fernandina Rice Rat, from which it is distinguished by its darker, brownish fur and dark, rather than white, feet. The rail is slightly shorter than the length of the head and body.

Behavior: Active at night.