--- title: "Tsetse Fly (Glossina morsitans) | AnimalTracks.wiki" description: "A blood-drinking fly that makes milk and gives birth to a larva nearly as big as she is." image: "https://animaltracks.wiki/images/animals/tsetse-fly-1.webp" published: "2026-10-11" updated: "2026-10-11" --- # Tsetse Fly (*Glossina morsitans*) > **Status**: Checked against 8 sources, listed under Sources below. > **Tagline**: A blood-drinking fly that makes milk and gives birth to a larva nearly as big as she is. > **Soundtrack Vibe**: Heavy UK Grime & Sub-Bass // Mala, "Lean Forward" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/7mM0r8goiVVSeVht6cshTV) > **Vibe Match**: A tsetse fly takes a blood meal almost as heavy as itself, then quickly passes out the extra water. Mala's Lean Forward drops a heavy sub-bass into sparse bars, then clears it away again. ## Biological Superpowers & Stats - **Taxonomy**: *Glossina morsitans* - **Danger Level**: Deadly - **Conservation Status**: Not Evaluated ([IUCN Red List](https://www.iucnredlist.org/)) - **Superpower**: Feeds its young on "milk" from glands inside the mother - **Habitat**: Savanna and shaded woodland in the lowlands of Africa - **Diet**: Blood, mainly from warthogs and other pig-family animals - **Tags**: insect, flying, hematophagy ## Natural History & Behavior ## A fly that nurses its young A female *Glossina morsitans* does not lay eggs. Animal Diversity Web says the embryo stays in her uterus, hatches there and is fed by "milk" glands in her reproductive tract. A study of the milk gland in *Glossina morsitans* calls it the tissue that passes nutrients and partner bacteria from mother to offspring. The larva (the young, grub-like stage) is nearly as big as the adult when she drops it onto loose soil. It has about an hour to dig in, then turns black and forms a hard case called a puparium. Pupae stay underground for about a month. The mother must take three blood meals to raise one young. Those bacteria matter. In lab work on *G. morsitans*, flies raised without the bacterium *Wigglesworthia glossinidia* as larvae grew into adults that were sterile and highly susceptible to *E. coli* infections of the body cavity. Normal adults of the same age resisted them. ## Size, weight and lifespan An adult *G. morsitans* is 7.5 to 14 millimetres long and brownish grey. In a lab colony of the subspecies *G. m. morsitans*, one-day-old adults averaged 20.4 milligrams for males and 22.0 for females. At 25 degrees Celsius, males in that colony lived 145.9 days on average, with a range of 9 to 241 days, and females lived 131.1 days, with a range of 4 to 208. Those are lab-reared flies, not wild ones. ## Blood and nothing else Both sexes feed exclusively on blood. They make anticoagulants, chemicals that stop clotting. The fly feeds in the daytime, is drawn to moving objects and reacts to the carbon dioxide animals breathe out. It is active only between 18 and 32 degrees Celsius. > **Gulp** Scientists who sequenced the tsetse genome report that flies of the genus *Glossina* take a blood meal almost equivalent to their own weight, and quickly pass out the excess water. ## Where it lives, and what it carries Animal Diversity Web places the species in Africa, in savanna in the wet season and shaded woodland in the dry season, always in the lowlands. In atlases of Zimbabwe and Zambia, the subspecies *G. m. morsitans* turned up in Zimbabwe's north and northwest and in south-eastern Zambia. Tsetse flies pass on the parasites that cause sleeping sickness in people and nagana in livestock. In 2014 the genome team put the number of people at risk of infection in sub-Saharan Africa at an estimated 70 million. In Zambia, researchers call *G. morsitans* the major vector, or carrier, of both the animal and the human forms of the disease. ## Frequently Asked Questions ### How many times can a tsetse female nurse young? The tsetse genome team reports that females can go through milk production 8 to 10 times in their lives without signs that their reproduction is wearing out. The team sequenced the subspecies *G. m. morsitans*, but states this of tsetse females in general. *(Source: [International Glossina Genome Initiative et al. 2014]())* ### Which animals does Glossina morsitans bite? A survey tested the blood in the guts of 29,245 wild-caught flies of eleven Glossina species. The morsitans flies in it fed mainly on members of the pig family, mostly warthog. In some areas hippopotamus or ruminants (cud-chewing animals such as cattle) replaced the warthog. *(Source: [Clausen et al. 1998]())* ### Which tsetse flies live in Zambia? Zambian researchers list six species and subspecies. Glossina morsitans is the most widely spread of them. The subspecies G. m. morsitans lives in the south-east, in the Luangwa-Lunsemfwa and Lower Zambezi tsetse belts, and G. m. centralis in the north-west. *(Source: [Muyobela et al. 2025]())* ## Sources 1. [Fraumann (2003). Glossina morsitans. Animal Diversity Web, University of Michigan.]() 2. [Chigusa et al. (1997). Relationship between longevity and body weight in Glossina morsitans morsitans. Medical Entomology and Zoology.]() 3. [International Glossina Genome Initiative et al. (2014). Genome Sequence of the Tsetse Fly ( Glossina morsitans ): Vector of African Trypanosomiasis. Science.]() 4. [Weiss, Wang & Aksoy (2011). Tsetse Immune System Maturation Requires the Presence of Obligate Symbionts in Larvae. PLoS Biology.]() 5. [Attardo et al. (2008). Analysis of milk gland structure and function in Glossina morsitans: Milk protein production, symbiont populations and fecundity. Journal of Insect Physiology.]() 6. [Clausen et al. (1998). Host preferences of tsetse (Diptera: Glossinidae) based on bloodmeal identifications. Medical and Veterinary Entomology.]() 7. [Muyobela et al. (2025). Developing a national atlas to support the progressive control of tsetse-transmitted animal trypanosomosis in Zambia. Parasites & Vectors.]() 8. [Shereni et al. (2021). An atlas of tsetse and animal African trypanosomiasis in Zimbabwe. Parasites & Vectors.]() *Published October 11, 2026. 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