Species Profile: Cross River Gorilla

Hello again, welcome back to animals under threat. Today, we will be covering a subspecies of Western Gorilla that is found near the Cross River in Nigeria. This subspecies was once considered to be extinct in the wild until scientists found a small population in 1980’s. Classed by the IUCN as Critically endangered and is one of Africa’s most endangered species. Say hello to the Cross River Gorilla (Gorilla gorilla spp. diehli).

This subspecies looks similar to the Western lowland Gorilla with the only differences in the skull size and tooth dimensions (Bergl et al, 2016). Cross River Gorillas prefer dense forest habitat but can live in riparian forests and high altitude grasslands. Their diet depends on which habitat they reside in as they prefer fruit during periods of seasonal abundance and herbs and bark through out the rest of the year (Etiendem & Tagg, 2013).

Photo of Cross River Gorilla eating by Nicky Lankester, Limbe Wildlife Centre (above) and Male gorilla by Wildlife Conservation Society (below).

 

Cross River Gorilla are one of the lesser known species as current studies estimated that there are 200-300 individuals left in the wild with estimated number of individuals in a group to be around 11 by examining nests left by the Gorillas (Funwi-Gabga et al, 2012). Each group is led by a male and the females and his young make up the rest of the group. Lead male Gorillas are sometimes called “silverbacks” due to the silver colour on their back (Worldwildlife.org, 2020).

Poaching, habitat destruction, climate change and inbreeding are some of the major threats to the Cross River Gorilla survival. Gorillas are sometimes caught in snares set by poachers to catch other animal species. The trapped Gorilla struggles to escape the snare this can result in injury or death. Habitat destruction of their major food sources for agricultural reasons has led to conflict between humans and Gorillas and with increasing climate change has force the Cross River Gorilla to move to other areas where they may be unable to survive in. Due to the small population, inbreeding is a big risk as lack of genetic flow between groups and lead to deformities in future generations and higher risk of diseases due to poor immune systems (Bergl et al, 2016).

Next time, we will be covering a species of wombat from Australia.

References

Bergl, R.A., Dunn, A., Fowler, A., Imong, I., Ndeloh, D., Nicholas, A. & Oates, J.F. 2016. Gorilla gorilla ssp. diehli (errata version published in 2016). The IUCN Red List of Threatened Species 2016: e.T39998A102326240.

Etiendem, D.N. & Tagg, N. 2013, "Feeding Ecology of Cross River Gorillas (Gorilla gorilla diehli) at Mawambi Hills: The Influence of Resource Seasonality", International Journal of Primatology, vol. 34, no. 6, pp. 1261-1280.

Funwi-Gabga, N., Funwi-Gabga, N., Mateu, J. & Mateu, J. 2012, "Understanding the nesting spatial behaviour of gorillas in the Kagwene Sanctuary, Cameroon", Stochastic Environmental Research and Risk Assessment, vol. 26, no. 6, pp. 793-811.

https://www.worldwildlife.org/species/cross-river-gorilla retrieved 28/6/2020

Picture references

https://www.iucnredlist.org/species/39998/102326240