Thryonomys swinderianus
greater cane rat

Thryonomys swinderianus is common in Africa, south of the Sahara. It ranges from Gambia to southern Sudan and from south to north Namibia and South Africa. Its range does not include the southwest portion of South Africa (Fritzinger, 1997).

T. swinderianus is found naturally near marshes and river banks (Mills, 1997). Populations can also reach very high densities in plantations of cultivated crops (Merwe, 2000). Its habitat is expanding due to farmers turning once undesirable forest land into farmland (Asibey,1999).

The body length of T. swinderianus is usually 350-610 mm, and their tail reaches 65- 260 mm in length (Fitzinger,1997). Great Cane Rats’ heavyset bodies have an average weight in males of 4.5 kg and 3.5 kg in females (Merwe, 2000). They have a rounded nose, short ears, and incisors that grow continuously (Mills, 1997). The pelage is coarse, with flattened bristle like hairs that grow in groups of five or six. The upper parts are a yellowish brown color and the underside is a much lighter gray. Great Cane Rats have no under fur (Fitzinger, 1997). The forefeet are smaller than the hind feet and have three well developed middle digits with the first and fifth digits greatly reduced. The hind feet have no first digit and all digits have heavy claws (Fitzinger, 1997). The dental formula for T. swinderianus is 1/1, 0/0, 1/1, 3/3 (Maerwe, 2000).

T. swinderianus live in groups of males and females during the breeding season. When the dry season comes males separate from the group and live by themselves. The females continue to live together (Fitzinger, 1997).

The breeding time depends on which part of Africa the animal is found and seems to depend on the weather (Fitzinger, 1997). The wet season of the year is the usual breeding season. Females generally have two litters per year with usually 4 offspring (Mills, 1997). Great Cane Rats estrous cycle usually lasts 6.62 days and they have a gestation period of 137- 172 days (Fitzinger, 1997). Offspring weigh about 129 grams and are relatively well developed. Their eyes are open, they are covered in hair and can run. T. swinderianus become sexually mature at about a year old (Fitzinger, 1997).

Fritzinger (1997) desribed a T. swinderianus that lived in captivity for four years and four months.

T. swinderianus can be usually found in groups composed of one male, several females, and young from more than one generation (National Research Council, 1991). They are nocturnal and create trails through grass and reeds that lead from shelter to feeding and water sites. They pound down tall grass to make nests and also make shallow burrows for shelter. They are good swimmers and divers (Fitzinger, 1997). If Great Cane Rats become afraid they either stomp their hind feet and grunt or quickly run towards water (National Research Council, 1991). Fitzinger (1997) describes males fighting by having a nose to nose pushing duel. He did not observe males fighting with females or young.

T. swinderianus are herbivores and their natural diet is mainly grasses and cane. Sometimes they also eat bark, fallen fruits, nuts and many different kinds of cultivated crops. Some of the cultivated crop fields that T. swinderianus invade are sugar cane, maize, millet, cassava, roundnuts, sweet potatoes, and pumpkins (Fitzinger, 1997). Great Cane Rats’ favorite food is elephant grass and sweet potatoes (National Research Council, 1991). They prefer plants with lots of moisture and soluble carbohydrates (Agbelusi, 1997).

T. swinderianus cut the grasses and other foods with their incisors, producing a chattering sound that is relatively loud and very distinguishable (Mills, 1997).

T. swinderianus is one of the most preferred meats in Africa and it can be more expensive than lamb, chicken, beef, or pork (National Research Council, 1991). It has been sold in Ghana markets for almost twice as much as beef and pork. In one African market, about 200,000 kg, which is worth about $220,000 U.S., was sold in a year’s time (Fitzinger, 1997). Asibey (1999) believes that if more research was done to find the most efficient way to breed T. swinderianus, then these animals would be the solution to Africa's protein shortage.

T. swinderianus are considered to be great pests of many cultivated crops and can do great economical harm to farmers (Merwe, 2000).

T. swinderianus population is not threatened by extinction, although individual populations may be extinct locally due primarily to over hunting (National Research Council, 1991).