Horn of Africa periodic monsoon winds and irregular rainfall. Mean daily maximum temperatures range from , except at higher elevations along the eastern seaboard, where the effects of a cold offshore current can be felt. Somalia has only two permanent rivers, the Jubba and the Shabele, both of which begin in the Ethiopian Highlands. About 220 mammals are found in the Horn of Africa. Among threatened species of the region, there are several antelopes such as the beira, the dibatag, the silver dikdik and the Speke's gazelle. Other remarkable species include the Somali wild ass, the desert warthog, the hamadryas baboon, the Somali
Horn of Africa Cinnamonifora due to the aromatic plants, or Regio Incognita owing to its unchartered territory. Shell middens 125,000 years old have been found in Eritrea, indicating the diet of early humans included seafood obtained by beachcombing. According to both genetic and fossil evidence, archaic Homo sapiens evolved into anatomically modern humans solely in the Horn of Africa between 200,000 and 100,000 years ago and have dispersed from the Horn of Africa. The recognition of "Homo sapien idaltu" as a valid subspecies of the anatomically modern human lineage would justify the description of contemporary humans with the subspecies name "H. s. sapiens".