If you thought that it’s only human beings, who plan timing of a baby birth, then think again.
Wildlife researchers have recorded that Nicobar long-tailed macaque (Macaca fascicularis umbrosus), endemic to the islands in the Bay of Bengal, choose to deliver infants during monsoon season when plenty of food is available for the lactating mothers.
A study published in the latest edition of the Current Science notes that although births occurred throughout the year, 71 per cent of the births were recorded in the wet season. This is perhaps because of higher availability of food resources in the wet season which may support lactation in females and provide food for the weaned infants, opined the researchers.
A total 69 births were recorded in the four main study groups of the macaques, of which 25 were males and 44 were females. The study was carried out from January 2013 to December 2015 in the Great Nicobar Biosphere Reserve, Great Nicobar Island.
Around 13.04 per cent of the births were recorded in July and November, whereas 3.26 per cent were recorded in February. But highest at 71 per cent were recorded during the monsoon months.
This is the first ever study to document and describe the group structure, demography and birth seasonality in the Nicobar long-tailed macaques , which are found on three of the Nicobar Islands-Great Nicobar, little Nicobar and Katchal.
lead author, Honnavalli N Kumara from Coimbatore based Sálim Ali Centre for Ornithology and Natural History pointed out that in contrast, another sub species M f fascicularis showed a May-July birth peak in peninsular Malaysia, whereas the population in northern Sumatra showed two birth peaks in July, and September-October.
In frugivorous macaques, breeding pattern strongly depends on seasonal fruit peak which is directly dependent on seasonal rainfall. Hence, phenology of fruiting trees (timing of fruit) of different geographical regions with even similar vegetal characteristics may differ with rainfall variation of that region, which can explain the variation in birth pattern in long-tailed macaques.
Despite their name, crab-eating macaques typically do not consume crabs as their main food source; rather, they are opportunistic omnivores, eating a variety of animals and plants. Although fruits and seeds make up 60 - 90 per cent of their diet, they also eat leaves, flowers, roots, and bark.
Yet another study conducted on the habit of the macaques in the Indian island, the researchers noted that the primates mostly showed preferences for slimy, hairy and thorny food, so to remove these coatings from food, they either wash it in puddles or wrap it in leaves and rub the coating off.
M f umbrosus in the island faces both anthropogenic pressures like habitat fragmentation and habitat loss, and natural disturbances like tsunami, cyclones, El Nino events, all of which have a negative impact on their existence.
Their conservation status as documented by the IUCN Red list is listed as 'vulnerable'.
The other researchers were Arijit Pal and Avadhoot D Velankari from Sálim Ali Centre for Ornithology and Natural History, Partha Sarathi Mishra and Mewa Singh from Biopsychology laboratory and Institution of Excellence, University of Mysore, Mysuru.
