Seeking the Somali Sengi

A Q&A with Djiboutian Research Ecologist Houssein Rayaleh

For Houssein Rayaleh, research ecologist and conservationist at Association Djibouti Nature, there was no doubt that the Somali Sengi still existed. What he did not know, however, was that the international scientific community was in search of the species, which had not been documented scientifically for more than 50 years. With the announcement of the recent rediscovery, we had a chance to connect with Houssein about his critical role in finding the Somali Sengi and helping sengi research specialists continue to get a better handle on the evolutionary family tree for a group of species that has been shrouded in mystery.

Q. How did you get involved in the search for the Somali Sengi?

A. My colleague and friend, Steven Heritage, who I did not know yet, contacted me by email in 2017 to inquire about sengis in Djibouti. He was connected with me by a mutual friend that we have at the Smithsonian Natural History Museum. Steven asked if Association Djibouti Nature (my organization) would collaborate on a small mammal survey in Djibouti, in search of sengis. Steven, Galen Rathbun and I became frequent correspondents and Association Djibouti Nature fully organized the preparations and logistics for the expedition. It was important to all of us that it be a collaborative project between in-country specialists on Djibouti wildlife and specialists that work on sengis. Each of us was active in the fieldwork. I was also involved with writing and editing the manuscript for the paper published in PeerJ.

Setting traps for the Somali Sengi on the 2019 expedition.
(Photo by Steven Heritage, Duke University Lemur Center)

Q. Were you hopeful that the sengi was still out there?

A. I have been a naturalist in Djibouti for most of my life and have spent 21 years doing different kinds of fieldwork, first as an elementary school teacher and head of elementary schools in several villages, and then as an ecologist and researcher in biodiversity, especially birds and mammals. I knew that sengis were present in Djibouti and on many occasions observed them at sites in different regions of my country. However, I did not yet know the true taxonomy of the sengis in Djibouti or that one of the possible species that is here might be considered “lost” to the international scientific community. No one knew the full details of sengis in Djibouti. As our paper indicates, sengis are regularly observed by Djiboutian people who still live a nomadic lifestyle. The local name for sengis, in the Somali language, is "wali sandheer."

Q. What makes this "rediscovery" so special?

A. For me, I was surprised that my foreign collaborators, Steven and Galen, were under the impression that it might be difficult to locate sengis in Djibouti. I knew that sengis inhabited several regions here and that if our team focused on sengis together, we had great potential for positive results. Also, we learned almost immediately from field identifications of the first individuals collected and kept at museums, that the sengis here were very likely the species called "revoilii." But I was surprised to learn of their rareness in the scientific literature. Months later, after the laboratory work was done, all of us were surprised to learn that the species would need to be a new genus.

The first scientific documentation of a live Somali Sengi.
(Photo by Steven Heritage, Duke University Lemur Center)

What does this "rediscovery" mean for the Republic of Djibouti?

For us living in Djibouti, and by extension the Horn of Africa, we never considered the sengis to be “lost.” But this new research does bring the Somali Sengi back into the scientific community, which we value. For Djibouti, it is an important story that highlights the great biodiversity of the country and the region and shows that there are opportunities for new science and research here. The Republic of Djibouti is home to diverse marine and terrestrial biomes which are under-explored or not explored at all. Natural history research in Djibouti is an important step in the country's renaissance—with respect to the lingering historical negative context of this former French colony. Previous negative references for Djibouti translate to: country whose flora is zinc palm, country where the jackal prays before crossing, and more recently, barracks country of the French foreign legion or military bases of world powers. We hope that one aspect of this research will demonstrate to the world that Djibouti is not a barracks for world militaries, but that our country harbors an unparalleled wealth of biodiversity to be discovered.

Why is it so important that we search for species lost to science and learn all that we can about them?

At this time of exponential development of industry and technology, where are we now? I believe that, in many ways, humans have cut themselves off from nature, even though nature has nourished them and continues to nourish them. A search for rarely documented species allows the scientific community to understand why they may be rare or lost, what conditions that lead to scarcity, and to develop recommendations to help prevent possible extinctions. This information can also be applied to species that are more common in ecosystems to prevent them from also becoming "lost" to science.