Animal Info - Bunker's Woodrat

(Other Names: Un Ratón)

Neotoma bunkeri (N. lepida b.)

Status: Endangered

1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where Currently Found, History of Distribution, Threats and Reasons for Decline)
4. Data on Biology and Ecology (Weight, Habitat, Gestation Period, Diet, Behavior, Social Organization)
5. References

Profile

Pictures: Related Species: Bushy-tailed Woodrat (Neotoma cinerea) (29 Kb JPEG) (Univ. Wash.); Southern Plains Woodrat (Neotoma micropus) (34 Kb JPEG) (Davis & Schmidly); White-throated Woodrat (Neotoma albigula) (79 Kb JPEG) (CPLUHNA)

Bunker's woodrat probably weighed more than 400 g (0.9 lb). Insular woodrats, such as Bunker's woodrat, are largely confined to rocky or boulder covered areas. Woodrats generally eat plant matter such as roots, stems and leaves; seeds, and some invertebrates. They do not drink much water, but during dry seasons they eat on the fleshy stems of cacti and other plants that are well filled with water. Woodrats are generally nocturnal and are active throughout the year. They are good climbers, but they usually do not climb far up in trees. Woodrats are solitary animals.

Bunker's woodrat has only been found on Coronados Island off of southeast Baja California, Mexico. Based on the complete lack of midden piles and debris from old woodrat houses on Coronados, Smith suggested that the animals have been extinct for years or even decades. She related the cause of this likely extinction to the fishermen who have used Coronados Island for some time as a site for fish camps. They brought in cats to control the mice that overran their camps, and they harvested for firewood the ironwood and other vegetation used by the woodrats as food. This appears to have led to the extinction of the woodrat on Coronados Island. (Smith 1993) Following a program of sampling rodent populations on islands in the Gulf of California from 1991 to 1999, the investigators consider Bunker's woodrat to be extinct (Alvarez-Castaneda & Ortega-Rubio 2003).

Tidbits

*** Bunker's woodrat had apparently evolved the largest body size of any insular woodrat (Smith 1993).

*** Woodrats collect a variety of material for their nests, often selecting pieces of silverware or other shiny objects from camps. This habit has given them the name of "trade rat" or "pack rat."

*** Sometimes woodrats live close enough to farms to be considered pests, but for the most part they have little economic significance.

Status and Trends

IUCN Status:

1994: Endangered
1996 - 2004: Endangered (Criteria: B1+2c) (IUCN 2004)

Countries Where Bunker's Woodrat Is Currently Found:

2004: Occurs in Mexico (IUCN 2004).

History of Distribution:

Bunker's woodrat has only been found on Coronados Island off of southeast Baja California, Mexico. Based on the complete lack of midden piles and debris from old woodrat houses on Coronados, Smith suggested that the animals have been extinct for years or even decades (Smith 1993). Following a program of sampling rodent populations on islands in the Gulf of California from 1991 to 1999, the investigators consider Bunker's woodrat to be extinct (Alvarez-Castaneda & Ortega-Rubio 2003).

Threats and Reasons for Decline:

"From the fragmented bits of evidence available and from interviews with local fisherman who visited the island [Coronados], we were able to piece together what we feel is a likely scenario for the extinction of this species. It appears that the island has been used for quite some time as a site for fish camps. The temporary structures in which the fishermen clean and gut their catch occupy virtually every cove and are in varying degrees of repair. According to the locals we spoke with, ‘mice used to overrun the camps' and cats were imported in order to reduce the problem... The fishermen also confirmed that ironwood and other island vegetation have been collected for camp fires. The end result was both the expiration of woodrat food resources and the introduction of previously unknown mammalian predators, a combination that has repeatedly proved disastrous for native fauna." (Smith 1993)

Data on Biology and Ecology

Weight:

Bunker's woodrat probably weighed more than 400 g (0.9 lb).

Habitat:

Insular woodrats are largely confined to rocky or boulder covered areas (Smith 1993).

Gestation Period:

Woodrats generally have a gestation period of 30 - 40 days.

Diet:

Woodrats generally eat plant matter such as roots, stems and leaves; seeds, and some invertebrates. They do not drink much water, but during dry seasons they eat on the fleshy stems of cacti and other plants that are well filled with water. (Nowak 1999)

Behavior:

Woodrats are generally nocturnal and are active throughout the year. They are good climbers, but they usually do not climb far up in trees. Bunker's woodrat constructed nests around large lava boulders and in the brush (Smith 1993).

Social Organization:

Woodrats are solitary animals.

References

Alvarez-Castaneda & Ortega-Rubio 2003, CPLUHNA, Davis & Schmidly, IUCN 1994, IUCN 1996, IUCN 2000, IUCN 2003a, IUCN 2004, Nowak 1999, Nowak & Paradiso 1983, Smith 1993, Univ. Wash.

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Last modified: February 12, 2005;