However, rodents selected as prey have ranged in size from the Southern African vlei rat ("Otomys irroratus") to the South African springhare ("Pedetes capensis") and the greater cane rat ("Thryonomys swinderianus"). There are records of predation on (the second largest African bat) straw-coloured fruit bats ("Eidolon helvum") and galagos of various sizes (usually weighing a kilo or less) but otherwise mammalian prey they pursue tends to be relatively larger. Locally, large numbers are taken of any species of hyrax. The attractiveness of hyraxes as a prey resource may encourage martial eagles to vary their hunting techniques to potentially more time-consuming perch hunting so that they may capture rock hyraxes from rock formations and tree hyraxes from trees, contrary to their usual preference for capturing prey on the ground in the open after soaring high. Ranging in average mass from , hyraxes can comprise a healthy meal for a family of martial eagle and are probably among the larger items that male eagles will regularly deliver to nests. Another miscellaneous mammal known to fall prey to martial eagles is the ground pangolin ("Smutsia temminckii"), although it is not clear the age pangolins that are preyed on and how they are dispatched, considering that adults weigh some and have a hard keratin shell that is capable of withstanding lion ("Panthera leo") jaws when in its rolled-up defensive posture. Although far less accomplished and prolific as a predator of monkeys than the crowned eagle, the martial eagle has been known to prey on at least 14 species of monkey. The monkeys to turn up most often as martial eagle prey are grivets ("Chlorocebus aethiops"), vervet monkeys ("Chlorocebus pygerythrus") and malbroucks ("Chlorocebus cynosuros"), with mean body masses of , and , respectively, because of their savanna-woods dwelling habits, tendencies to forage on the ground and their primarily diurnal activity. Similarly, the larger Patas monkey ("Erythrocebus patas"), at , also dwells in similar habitats and so may be subject to occasional predaceous attacks. There's evidence that these monkey species have special alarm calls, distinct from those uttered in response to the presence of a leopard ("Panthera pardus") for example, specifically for martial eagles.