• Mutualism can be found throughout the animal kingdom. Mutualism is a relationship between two different species, where each species gains something from the association. The common warthog (Phacochoerus africanus) has been documented in what appears to be mutualistic relationships with several other species.

    The common warthog ranges widely throughout sub-Saharan Africa. Though its habitat is primarily in the savannas, bushlands, and woodlands, it can also be found in forests in the mountains of East Africa. The warthog is a grazer, eating mostly grass, roots, and berries, though it will also sometimes eat carrion.

    Like many large grazing animals in parts of Africa, the warthog is often groomed by oxpeckers. These birds will perch on a warthog’s back and pick and eat ticks and other parasites from its skin. But the oxpeckers are not the only animals that warthogs are groomed by, and the other relationships are a bit more unusual.

    While mutualistic relationships are common in nature, they are not common between two species of mammals. In fact, warthogs are participants in the first known example of a mutualistic relationship between two mammals that aren’t primates. Researcher Andy Plumptre documented warthogs in Queen Elizabeth National Park in Uganda laying down to let a pack of banded mongooses climb over them, eating the ticks that are feeding on the warthogs. Tourists have also reported this odd behavior.

    Warthogs have another unusual grooming companion—the southern ground hornbill. The hornbill is not known to groom any other animal, but that isn’t what makes their grooming interaction with warthogs so interesting. According to scientists who have observed the behavior, the warthogs are the ones who take the initiative. They approach the very large birds and then lay down on their sides to be groomed. The birds seem to be careful with their large beaks, which are capable of killing a tortoise, even grooming sensitive areas around the warthogs’ ears and tails.

    1. In a mutualistic relationship between species, each animal is thought to benefit in some way from the association. How does the warthog benefit from its relationships with the oxpeckers, mongooses, and hornbills? How do those animals benefit?

      The warthog benefits by having annoying and possibly harmful parasites removed. The other animals benefit by having a food source.

    2. One possible explanation for the unusual behavior between the warthogs and hornbills is that they are in a game reserve, where they are protected. How might this influence their behavior?

      The relative lack of threats might make the animals more relaxed and trusting. They may also be in closer contact with each other than they would be otherwise.

    3. Humans are also involved with mutualistic relationships with other species. What are some examples?

      Answers will vary. Some common examples are dogs and other domesticated animals as well as gut bacteria. There are also people in Africa who cooperate with the honeyguide bird to find wild honey. In Brazil, a group of bottlenose dolphins have reportedly cooperated with local fishermen to catch fish since the late 1800s.

  • Term Part of Speech Definition Encyclopedic Entry
    carrion Noun

    flesh of a dead animal.

    graze Verb

    to feed on grass, usually over a wide pasture.

    groom Verb

    to tend or carefully clean, brushm and make tidy.

    mammal Noun

    animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

    mutualism Noun

    relationship between organisms of different species, in which both organisms benefit from the association.

    mutualistic relationship Noun

    relationship between organisms of different species, in which both organisms benefit from the association.

    oxpecker Noun

    African bird (starling) that perches on the backs of cattle and wild mammals to feed on their ticks.

    savanna Noun

    type of tropical grassland with scattered trees.

    sub-Saharan Africa Noun

    geographic region located south of the Sahara Desert in Africa.