ic ▁shr ub lands . ▁ ▁A ▁study ▁conducted ▁in ▁a ▁x er ic ▁shr ub land ▁of ▁north western ▁Venezuela ▁found ▁that ▁females ▁of ▁Mar m osa ▁ro bin son i ▁increase ▁in ▁mass ▁three ▁time ▁faster ▁than ▁males . ▁The ▁same ▁study ▁also ▁found ▁that ▁individual ▁of ▁both ▁sex es ▁typically ▁are ▁active ▁in ▁areas ▁of ▁approximately ▁ 2 5 ▁m ², ▁but ▁pre gn ant ▁females ▁dram atically ▁reduce ▁such ▁area ▁to ▁ca . ▁ 1 – 6 ▁m ². ▁There ▁are ▁observations ▁that ▁M . ▁ro bin son i ▁fe eds ▁on ▁f ruits ▁of ▁column ar ▁c act i , ▁although ▁the ▁species ▁is ▁also ▁expected ▁to ▁pre y ▁on ▁insect s ▁( as ▁many ▁did el ph ids ▁do ). ▁In ▁Venezuela , ▁spec im ens ▁inhab iting ▁agricult ural ▁lands ▁and ▁dist urbed ▁for ests ▁are ▁larger ▁than ▁those ▁from ▁cloud ▁and ▁gallery ▁forest ▁likely ▁due ▁to ▁the ▁higher ▁product ivity ▁of ▁the ▁former ▁habit ats . ▁ ▁Be havior ▁Mar m osa ▁Robinson i ▁generally ▁first ▁appears ▁as ▁sun set ▁and ▁is ▁active ▁inter mitt ently ▁until ▁sun r ise . ▁These ▁activity ▁periods ▁usual ▁begin ▁with ▁a ▁gro oming ▁session ▁with ▁special ▁attention ▁given ▁to ▁the ▁face ▁and ▁sn out . ▁Based ▁on ▁current ▁observations ▁it ▁appears ▁to ▁be ▁a ▁solit ary ▁species ▁in ▁the ▁wild . ▁Capt ivity ▁showed ▁the ▁formation ▁of ▁social ▁hier arch ies . ▁This ▁hierarchy ▁is ▁related ▁to ▁reprodu ction ▁and ▁involves ▁the ▁males ▁as ser ting ▁their ▁domin