Elephant Shrews or Sengis: Small Animals with Long Noses
What is an Elephant Shrew?
An elephant shrew is a small mammal with a long, projecting nose that is constantly moving and sensing the environment. It's known as an "elephant" shrew because its flexible and mobile nose reminded earlier scientists of an elephant’s trunk. The projection is technically known as a proboscis. The animal has a hunchbacked posture, long, slender legs and a scaly, mouse-like tail, giving it a curious appearance.
Elephant shrews live in Africa. They aren’t actually shrews, despite their name, and they aren't rodents either, despite the appearance of their tail. They are related to tenrecs, aardvarks, manatees, hyraxes and elephants. Some people prefer to call elephant shrews sengis, a word that comes from the Bantu language.
A Giant Sengi at the Houston Zoo
Types of Elephant Shrews or Sengis
According to the latest classification scheme, nineteen different species of elephant shrews are recognized. (Some sources recognize only sixteen species.) The animals are divided into two groups. The giant elephant shrews may reach twelve inches in length, not including the tail. They often have vivid colors and weigh about a pound each. The animals in the second group are known as soft-furred elephant shrews and are much smaller. They weigh up to around seven ounces and have less colorful grey or brown coats.
The Four Giant Elephant Shrew Species
Black and rufous
There are fifteen species of soft-furred elephant shrews. One belongs to the genus Petrodromus, three to the genus Macroscelides and eleven to the genus Elephantulus. The population status of most of the soft-furred elephant shrews is not a concern at the moment.
Hunting and Foraging
Sengis live in many parts of Africa in a variety of habitats. They are found in forest, scrubland, savanna or semi-desert areas, depending on the species. Giant sengis are generally found in forest and dense woodland and are active during the day. The smaller animals are usually found in grassland and drier areas and are often active in the early morning and late evening.
Sengis have a good sense of smell and also see and hear well. They are omnivorous creatures but feed mainly on other animals. They eat a lot of insects as well as some spiders, centipedes and millipedes. They occasionally include earthworms in their diet. Small sengis also eat a significant amount of fruit, seeds and leaves.
A sengi roots out its prey with its long, probing proboscis. The smaller species have a shorter proboscis than the giant ones. Once food is found, the animal extends its long tongue to pick up the prey. The tongue typically flicks the food into the mouth.
Round-Eared Sengi (Macroscelides micus)
Some elephant shrews create trails in the leaf litter or grass. They patrol these trails regularly as they look for prey. The trails also provide a very important escape route during times of danger.
Elephant shrews have powerful back legs and are capable of moving fast and jumping high relative to their size. They often move by a combined running and hopping motion, especially when they are trying to avoid a predator. They've also been observed slapping their tail against the ground or drumming their feet in times of stress.
An Elephant Shrew Travels along its Escape Trails
The elephant shrews that have been studied are monogamous, which means that the same male and female pair up each time mating takes place. The pair share the same territory or occupy neighboring territories, but they have little to do with each other except during mating.
The male and female have separate nests. They often create their nest by digging a hole in the ground or by using a hole created by another creature. They may also build a nest in a rock crevice or another protected area. The nests are generally lined by leaves.
Elephant shrews mark their territory with secretions from glands that are located in several places on their bodies, including around the anus, on the feet, under the tail and on the chest. They detect the presence of another animal's secretions with their sense of smell. Males will drive other males away from the area and females will protect the area from other females. Encounters with invaders are often violent.
Elephant shrew gestation lasts for 45 to 60 days. The litters are small and consist of just one to three offspring. Several litters may be born in a year. In at least some species, the babies are born in a separate nest from the mother's regular sleeping nest.
The babies have mature features at birth. Their hair has formed and their eyes are open. They can move around after only a few hours. They remain hidden in the nest for the first three weeks of their life, however. The youngsters then emerge and follow their mother around for about a week. At the end of this time they are weaned.
After weaning, the youngsters stay in their mother's territory for about six more weeks before they leave to establish a territory of their own. Elephant shrews usually live for two to five years, depending on the species.
A Baby Elephant Shrew at the Smithsonian Zoo
Although the elephant shrew's highly mobile proboscis is reminiscent of an elephant's trunk, it's hard to imagine that the little elephant shrew and the giant elephant are related. Researchers say that the DNA evidence supports this relationship, however.
Scientists have created a classification group called the Afrotheria. This group includes elephant shrews, elephants and other animals. The scientists say that all the present members of the group evolved from a common ancestor in Africa.
The Afrotheria group includes the following animals. The numbers in brackets refer to the pictures shown in the collage below.
- aardvarks (1)
- dugongs (2)
- elephant shrews or sengis (3)
- manatees or sea cows (4)
- golden moles (which are different from "true" moles) (5)
- hyraxes (6)
- elephants (7)
- tenrecs (8)
IUCN Red List Categories Describing Population Status
Red List Abbreviations and Meanings
LC - Least Concern
NT - Near Threatened
VU - Vulnerable
EN - Endangered
CR - Critically Endangered
EW - Extinct in the Wild
EX - Extinct
A Data Deficient or DD category and a Not Evaluated or NE category are sometimes added to the Red List categories.
Population Status of Elephant Shrews
The IUCN (International Union for Conservation of Nature) maintains a Red List of organisms. This list contains animals and plants categorized according to their risk of becoming extinct. Most of the soft-furred elephant shrew populations are classified in the Least Concern category, but a few are categorized as Data Deficient. The latter term indicates that we don't have a good estimate for the number of animals that exist so we can't make a decision about their population status. The giant elephant shrews are classified in the Near Threatened, Vulnerable or Endangered categories.
Threats to Giant Sengis
Elephant shrews are eaten by predators such as birds of prey, snakes and lizards. In some areas, humans kill elephant shrews for food. The chief problem faced by giant sengis is the loss and fragmentation of their habitat, however. As trees are logged to clear land for agriculture or buildings, the amount of land available for the sengis decreases.
Habitat loss and fragmentation are growing problems for wildlife in many parts of the world today as humans become increasingly dominant in the landscape. The term "fragmentation" means that suitable habitats for an animal are restricted to small areas that are separated from each other. Fragmentation can be dangerous for a population because it reduces the chance that unrelated males and females will meet and mate. This reduces genetic diversity and health in the population.
Conservation organizations are working to protect wildlife such as giant sengis while also trying to meet the needs of humans. Both goals are important in our world today.
© 2011 Linda Crampton