The park is of global significance for its biodiversity and endemism. It is home to many species and habitats that exist nowhere else. 80% of the areas over 3000m in Africa are in Ethiopia, and much of this is within the Simien Mountains. 

Although numbers vary depending on who you listen to, it’s believed that over 20 large mammals and 130-200 bird species live in the park. As you trek across the Simiens, you’ll encounter the endangered Walia Ibex, the Ethiopian Wolf (or Simien Fox) which is the rarest canid species in the world and the rather wonderful Gelada Monkey (often called the Gelada Baboon, but not technically a baboon!).

The Simiens was one of the first places to be given the title of a World Heritage Site in 1978. In 1996, it made it onto the less desirable World Heritage in Danger list, due to the decline in the population of Walia Ibex as a result of human settlement, grazing, roads and other influences.

By far the most famous of all the wildlife in the Simiens, Gelada Monkeys are found in abundance in the Simien Mountains. With numbers estimated at over 5000, you’re all but guaranteed to bump into troops of these amazing animals on any Simien trip. They’re easy-going and likely to be the most photographed creatures you’ll encounter as they are fairly tame and peaceful.

They have a distinct, hourglass shaped patch over their chests, which has led to their common name, the ‘bleeding heart monkey’. Gelada’s are endemic to the Simien Mountains and live at elevations of 1800-4400m, sleeping in cliffs and the patrolling the grasslands for food – grasses, seeds, roots and insects (rarely). They are the only primates that are mainly graminivores (grazer) with grasses constituting 90% of their diet.

They move in troops. At night, they often descend from grazing areas to caves – it’s a wonderful site to watch hundreds of monkeys climbing (and sometimes tumbling) down steep slopes to their night-time spots, which they rest in for safety against predation as well as for warmth. Males, distinguishable by their ‘mane’ of hair, will have a harem of females and these harems often live together, defending against single males. The Gelada has a vocabulary of at least 27 contact calls, an unusually large number.

You’ll be very luck to spot an Ethiopian Wolf on your journey, also known as the Red or Simien Fox. There are just 100 in the park (in 1977 there were only 20 left). If you’re desperate to spot one, the Bale Mountains in southern Ethiopia offers a better chance of sightings. 

Living at 3500-4000m the wolf is a specialised feeder of rodents and has very specific habitat requirements, which have contributed to its status as Africa’s most endangered carnivore and one of the world’s rarest canids, with an estimate of 360-400 individuals in the world in 2011, the majority living in the Bale Mountains National Park.

Another animal endemic to the park is the Walia Ibex (or Abyssinian Ibex). It is estimated that there are just 500-900 of them left, and they have been credited with the parks Heritage status. It was reduced to 250 animals at its lowest, but numbers have recovered slowly with an estimate of ~600 in 2006.

Surprisingly, it is the only goat endemic to sub-Saharan Africa. The Ibex is a species of mountain goat with fantastic horns, that live on the giant cliff faces. Visitors might have to swallow feelings of vertigo to spot them clinging to the edge of precipitous slopes.

Predated by hyenas, the Ibex went from endangered to critically endangered in the 1990s due to poaching. The Walia Ibex live at 2500 to 4500m above sea level. Walia Ibex tend to live in herds of 5 to 20 and have a striking colouration, with the males owning the better headpiece!

If you are camping in the Simien Mountains, Chennek camp is where you’ll get the best chance of spotting Walia Ibex.

Between 130 and 200 bird species exist in the Simiens, depending on whose numbers you believe! 5 are endemic to Ethiopia and 12 ‘near-endemics’. The Simiens is an excellent place for birding.

Species include the striking thick-billed raven, wattled ibis, white-collared pigeon, spot-breasted plover, white-billed starling, white-backed black tit and many, many others. There are said to be 25 species of raptors in the park, 5 vultures and four eagle species.

Perhaps the most famous is The Lammergeyer, or bearded vulture, which isn’t endemic but is fascinating. It is the only bird which eats almost exclusively bone marrow. It will carry bones up to a height and then dropping them in order to break them apart and get at the marrow within.

As well as the birds and the beasts, the Simien Mountains are often as interesting underfoot with over 250 types of plant existing in the park. Walks in these mountains are an olfactory delight, with abundant thyme and other herbs, tussocks and grasses.

Above 3,700m is generally open grassland, punctuated by solitary trees as well as many Giant Lobelia’s, which can measure up to 10m in height. A stonecrop Rosularia simiensis is endemic to the Simiens, as are ten of the different grass species, including some grasses that are endemic to the Geech plateau.

Between 3,700m and 3,000m, otherwise known as the Ericaceous belt due to the number of Erica bushes, trees and bushes begin to flourish.

Beneath 3,000m much of the forest has been felled for firewood and the land turned into grazing or arable land, and as a result much of the diversity has been lost, with little regeneration. However, on more precipitous areas many of the original cover remains including Acacia and Ethiopian Tid as well as other sclerophyllous trees.