Just before the river enters KNP, some three large mines utilise the Olifants as a water source for operations. This is the one of the major sources of metal pollution in the river. Of all the six major rivers crossing KNP, the Olifants has the highest density of crocodiles, some 2500 individuals, and the total population for the park is an estimated 4600. The population in the study area varied from a low 62 to a high 697 individuals at different times of the year. The study in the Olifants river comprised of 11 large crocodiles, all larger than 3 m total length, fitted with radio transmitters and monitored over 2 years.
All sizes are total length.
Seven males and 4 females were radio-collared, but 3 transmitters were lost in rapid succession shortly afterwards. None could be retrieved. The round trip was about 32 km. The remaining five males varied from 3.3 to 4.3 m in length and all moved from their initial capture sites with one returning and the other four remained in Mozambique. A male of 4.1 m moved the shortest distance of 9.3 km and the longest distance of 32 km was covered by a male of 3.7 m.