Kenya started marking rhinos on Thursday (April 5) and aims to tag and identify 22 of them in two weeks at a cost of $600,000, senior government officials said on Thursday, as part of conserving their dwindling numbers.

The project comes just weeks after the world’s last male northern white rhino died in Kenya, leaving only two females of its kind alive in the world. Scientists still hope to save the subspecies from extinction using in vitro fertilisation.

Kenya Wildlife Service (KWS) and the Ministry of Tourism started marking the rhinos in Meru National Park, the area of which is being increased to 83 square km from 45 square km previously.

Head of veterinary services at KWS, Francis Gakuya told Reuters that ear notches, which are permanent markings, can be used for the life of the animal whereas horn transmitters have a shelf life of two to three years before the battery runs down.

The numbers of rhinos in the park have risen to 104 from 90 previously. Of those, 72 are southern white rhinos and 32 are black.