In particular, Morel believed that Africans, lacking the self-discipline of whites, had an uncontrolled sexuality and often wrote about that subject. Morel believed that because of the high infant mortality in the tropics that Africans had evolved in such a way as to be obsessed with sex, to the exclusion of everything else, as they needed a high birth rate to maintain their numbers. Precisely because Morel believed in the uncontrolled sexuality of blacks, he considered it self-evident that the "sexually uncontrolled and uncontrollable" Senegalese would run amok in the Rhineland and rape every German female in sight. Two contemporaries challenged Morel on that: Claude McKay, the Jamaican poet and labour activist, and Norman Leys, the British Africanist. Leys stated that such allegations constituted "one of the great sources of race hatred" and "should never be repeated by any honest man or honest newspaper".