The other situation is if mom has O type blood. The same thing can happen as with the (-) and (+) blood type difference, but it is not as severe. If mom has O+ or O- blood type, and the baby has A+, A-, B+, B-, AB-, or AB- blood type, an ABO incompatibility can develop.
Why do howler monkeys howl? Howler monkeys live in family groups in the rain forests of South America. They howl so that other monkey groups do not stray into their territories. The sound also helps group members stay in contact with each other. Monkeys are communal animals that live in exclusive groups.
They are arboreal creatures, spending most of their time in the treetops foraging for food, and rarely descend to the forest floor. Howler monkeys are the largest of all New World monkeys and have a lifespan of seven to fifteen years. Habitat: Mantled howler monkeys can be found in the canopies of both lowland and montane rainforests. They are commonly heard long before they are seen searching for leaves in the treetops. A troop of howler monkeys usually consists of eight to twelve females, three or four dominant males and several young.