In past ages bigger parts of Uganda was covered by forests. The forests retracted and made place for the savannas as consequence of fire-clearing the people and grazing pressure of the big animals. Especially elephants are able to keep huge areas open. The grasslands in Uganda are generally wetter and bushier than those in other East-African countries. This allows a variety of animals to graze on grasslands and take cover among the trees. One of the animals specialized to life in wet savannas is the Uganda kob. Uganda kobs together with the crowned crane are national animals of Uganda. In some savannas national parks in the country the elephants and buffalos are hybrids of the forest and grassland races.