Eritrea’s landscape includes three distinct regions, the green highlands, the hot, dry western lowlands, and the long coastal plain, moreover; Eritrea is home of several rare species like the Nubian ibex and the African golden wolf, it also has a healthy population of northern African elephants, it’s also home of the world’s only population of free-ranging African wild donkeys.
Wildlife reserves in Eritrea:

1. Yob Wildlife Reserve
(2,658 Square Km) – Location
Yob Wildlife Reserve is a protected area in the Northern Red Sea and Anseba regions of northern Eritrea. It covers an area of 265,800 hectares, established on 16 March 1959 by the British specifically to protect the significant populations of Nubian ibex in the area, its protection was reaffirmed on 1 January 1975. The reserve is under the Wildlife Conservation Department of the Eritrean Ministry of Agriculture.

2. Nakfa Wildlife Reserve
(1,639 Square Km) – Location
Nakfa Wildlife Reserve is a protected area in Eritrea in the Northern Red Sea Region. It is located in the Afabet district. It was designated a reserve by the British administration as early as 1959 and developed by volunteers from the US Peace Corps as early as the 1960s.

3. Gash-Setit Wildlife Reserve
(709 Square Km) – Location
Gash-Setit is found in the Gash-Barka Zone of Eritrea since 1991, it’s a historical area of western Eritrea where it is considered to be the northernmost point of Africa for elephant habitat. It is located in much of Omhajer District and Haykota District between the southwest of Haykota and the market town of Tesseney in the Gash-Barka region.

"Eritrea is home of the world’s only population of free-ranging African wild donkeys"
Eritrea has more than 500 native bird species. The country is on a widely used migratory bird path that links the Middle East and Africa. The coastal waters are home of whales, dolphins, dugongs and five species of sea turtles.
Animals “back from the dead”:
Eritrea has two native animals who “came back” from extinction.
1. The Eritrean Gazelle (Eudorcas tilonura) or Heuglin’s Gazelle:
This rare gazelle was listed as extinct until a conservationist came across a small herd of them 90 years later. Biologists confirmed they were Eritrean gazelles. The Eritrean government has set aside land to conserve these rare, beautiful gazelles.

2. Eritrea side-neck turtle (Pelomedusa gehafie):
Like the Eritrean gazelle, this turtle was declared extinct. Scientists had not seen one for almost 100 years. In 2016, conservationists discovered a small population of the turtles.

"The Eritrean Gazelle was listed as extinct for 90 years, and the Eritrean side-neck turtle for almost 100 years"
Eritrea’s endangered animals also include the Dorcas gazelle and Soemmering gazelle. The numbers of Eritrea’s native animals have diminished due to deforestation, the war of independence, and the border dispute with Ethiopia. The Eritrean government has passed laws to protect the country’s native flora and fauna.
Furthermore, the government of Eritrea outlawed the hunting and trapping of wild animals and banned the cutting of live trees. It has also set aside areas such as wildlife preserves, national parks, and marine reserves. Eritrea instituted a tree-planting program to reverse the effects of deforestation.
In addition, there are many places to see wildlife in Eritrea. Visitors can spot lions and greater kudus in the mountain regions. In the Denkalia region, elephants and gazelles roam. In the Nakfa and Gash-Setit wildlife parks, you will see bushbucks, duikers, greater kudus, klipspringers, leopards, oryxes, and crocodiles.

"The Eritrean government has passed laws to protect the country’s native flora and fauna"
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Sources:
AZ Animals.com
Wikipedia – Yob Wildlife Reserve
Wikipedia – Gash-Setit
National Parks Tours Worldwide