Other ungulates are taken by Nile crocodile more or less opportunistically. These may include Grévy's ("Equus grevyi") and plains zebras ("Equus quagga"), pygmy hippopotamus ("Choeropsis liberiensis"), warthogs ("Phacochoerus africanus"), bushpigs ("Potamochoerus larvatus") and red river hogs ("Potamochoerus porcus"). In Maasai Mara, Tanzania, large crocodiles congregate at river crossings used by migrating herds of Burchell's zebras and blue wildebeests ("Connochaetes taurinus"), picking off hundreds of these large ungulates annually. All domesticated ungulates and pet animals will on occasion be hunted by Nile crocodiles, up to the size of dromedary camels ("Camelus dromedarius") and cattle ("Bos taurus") In Tanzania, up to 54 head of cattle may be lost to crocodiles annually, increasing the human-crocodile conflict level. Goats ("Capra aegagrus hircus"), donkeys ("Equus africanus asinus") and dogs ("Canis lupus familiaris") may also rank among the most regularly recorded domesticated animals to be taken by Nile crocodiles.