Rhodesian giraffe, Luangwa giraffe
Thornicroft's giraffe (Giraffa camelopardalis thornicrofti) is a subspecies of giraffe that lives only in Zambia’s South Luangwa Valley. This subspecies lives only in the wild, with no captive populations. It was originally named after Harry Scott Thornicroft, a commissioner in what was then North-Eastern Rhodesia and later Northern Rhodesia.
Thornicroft's giraffes are tall with very long necks. They have long, dark tongues and skin-colored horns. Giraffes have a typical coat pattern, with regional differences among subspecies. The pattern consists of large, irregular shaped brown to black patches separated by white to yellow bands. Male giraffes' coats darken with age, particularly the patches. The darkening of the coat has not been studied extensively enough to indicate absolute age; however, it can estimate the relative age of male Thornicroft's giraffes.
Thornicroft's giraffes are found only in the Luangwa Valley, eastern Zambia. Within this restricted range, they inhabit arid and dry-savanna zones, riparian forest, woodlands, scrub brush, and open grassland.
Generally, giraffes are found in groups that vary in size and composition. These groups are usually sex-segregated although mixed-sex groups made of adult females and young males also occur. Young males also form groups and engage in playfights. However, as they get older, males become more solitary but may also associate in pairs or with female groups. Giraffes are not territorial, but they have home ranges that vary according to rainfall and proximity to human settlements. Males occasionally roam far from areas that they normally frequent. Male giraffes use their necks as weapons in combat, a behavior known as "necking". Necking is used to establish dominance and males that win necking bouts have greater reproductive success. Giraffes browse during the first and last hours of the daytime. Between these hours, giraffes mostly stand and ruminate. Rumination is the dominant activity during the night when it is mostly done lying down.
Thornicroft's giraffes are herbivores (folivores, lignivores, frugivores). They are exclusively browsers that primarily feed on leaves, tree bark, and shoots of trees and shrubs. They consume deciduous plants in the wet season and transition to evergreen and semi-evergreen species in the dry season, choosing flowers, fruits, and pods when they are available. They can obtain their water through the foliage they consume, but drink regularly when water is available. Giraffes usually seek out acacia species when browsing.
Giraffes are polygynous, meaning that males mate with multiple females. Thornicroft's giraffes breed throughout the year. Usually, males engage in combats, after which the winner gets right to mate with receptive females whenever and wherever it finds them. Normally, the gestation period lasts 13-15 months, yielding a single baby, rarely - twins. The female gives birth in a calving area, which she further uses throughout her life. A newborn calf can walk in just an hour after birth and can run within 24 hours after birth. Thornicroft's giraffes become reproductively mature at approximately 6 years of age and then produce offspring approximately every 677 days.
The primary threats to Thornicroft's giraffes are poaching, human population growth, habitat loss, habitat fragmentation, and habitat degradation. Since Thornicroft’s giraffes live in only one limited location, such anthropogenic factors, as water pollution, climate change, diversion of water for agriculture or mining, and epidemic diseases may affect the population and then the entire subspecies could be devastated.
According to IUCN Red List, the total population size of the Thornicroft's giraffe is 600 individuals or around 420 mature individuals. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List but its numbers today are stable.
Giraffes have a great effect on the trees that they feed on, delaying the growth of young trees for some years and giving "waistlines" to too tall trees. In addition, when spotting a predator, they can serve as a warning system for other nearby animals.