THE MOSAIC OF COLOURS 



have inconspicuous coats; brown and yellow are their most usual 

 colours, and these are on the whole the colours of the ground over 

 which they move, or the tree-trunks against which they sleep. For 

 most of the mammals go about their business in the night ; by day 

 they sleep, and hence, unless they take refuge in burrows, they have 

 especial need of protective coloration. 



But those mammals which, like the birds, have adopted a diurnal 

 and arboreal existence, have evolved on quite different lines. It is 

 as though an active life in the sunlight and the open air had made 

 their blood course more swiftly, for, like the birds, the squirrels and 

 monkeys are very vivacious creatures, and are seldom still. Their 

 special means of escaping their enemies is their agility, and so in 

 them protective coloration is of less importance; indeed, the arboreal 

 mammals would find it difficult to adopt such coloration, as the 

 background to which they would have to adapt themselves is 

 continually changing : now it consists of green leaves, now of brown 

 tree-trunks, and now of the blue sky. In the night, when the animals 

 sleep, they need no protective coloration, since "in the dark all 

 cats are grey." 



This being so, audible or visible signals of recognition are all the 

 more important for arboreal mammals. They cannot follow the 

 members of their own species by their odour, since they constantly 

 break their trail by leaping from bough to bough, and no scent will 

 lie in the air. The monkeys, therefore, must rely on sight and 

 hearing. Anyone who has ever visited a zoological garden knows 

 that the monkey-house is always vocal, while among the Ungulates 

 all is quiet. Brehm tells us of a little South American monkey, 

 Leontocebus oedipus, a relative of the Saguim, that he was always 

 impressed by the similarity of its voice to that of a bird. This monkey 

 "sings," now in pure, long-drawn, fluting notes, and now in trills, 

 in every imaginable key. Since this musical monkey has long white 

 hair hanging to his shoulders, like that of a musician, he has been 

 humorously nicknamed the "Liszt monkey." 



The Guaribas or Howler Monkeys also sing in concert, and 

 according to Miiller-Munchen the result is by no means an unmusical 

 howling; indeed, the Brazilians call it singing. The "chaplain" 

 leads off, at first in short, staccato notes, and then in full, organ- 

 like tones, while the others sing a gentle "accompaniment," as 

 though anxious lest they should drown the chaplain's voice, as 

 a too noisy orchestra may submerge the voice of a singer. The 

 tongue of the Howler Monkey lies above a great bony drum, and 



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