Roan antelope
Roan antelope are found in woodland and grassland savanna, mainly in the tropical and subtropical grasslands, savannas, and shrublands biome, which range in tree density from forest with a grassy understorey (such as central Zambezian Miombo woodlands) to grasslands dotted with few trees, where they eat midlength grasses. They form harem groups of five to 15 animals with a dominant male. Roan antelope commonly fight among themselves for dominance of their herd, brandishing their horns while both animals are on their knees.
Antlion
Depending on the species and where it lives, the larva either conceals itself under leaves, debris or pieces of wood, hides in a crack or digs a funnel-shaped pit in loose material. As ambush predators, catching prey is risky because food arrives unpredictably and, for those species that make traps, maintaining one is costly; the larvae therefore have low metabolic rates and can survive for long periods without food. They can take several years to complete their life-cycle; they mature faster with plentiful food, but can survive for many months without feeding. In cooler climates they dig their way deeper and remain inactive during the winter.
When the larva attains its maximum size, it pupates and undergoes metamorphosis. It makes a globular cocoon of sand or other local substrate stuck together with fine silk spun from a slender spinneret at the rear end of the body. The cocoon may be buried several centimetres deep in sand. After completing its transformation into an adult insect over the course of about one month, it emerges from the case, leaving the pupal integument behind, and works its way to the surface. After about twenty minutes, the adult's wings are fully opened and it flies off in search of a mate. The adult is considerably larger than the larva as antlions exhibit the greatest disparity in size between larva and adult of any type of holometabolous insect. This is by virtue of the fact that the exoskeleton of the adult is extremely thin and flimsy, with an exceptionally low density. The adult typically lives for about 25 days, but some insects survive for as long as 45 days.