Houston Zoo in Texas, US, has opened its new African Forest exhibit.

The US$40m, 6.5-acre development was first mooted six years ago and took 18 months to build.

The exhibit is home to chimpanzees, rhinos, kudu antelope and giraffes.

The centrepiece of the African Forest is the new chimpanzee habitat, where the chimps can retire to at night.

A spokesperson for the zoo said: "In the old days of zoo design, most night time animal holding areas were not much more than small, dark, sterile cubicles. Our new chimp building is raising the bar to a new standard of comfort and spaciousness.

"With an indoor living space of over 4,000sq ft, our chimps will be living in the lap of luxury."

The chimp house also has its own kitchen, food storage, computer area and bathroom for staff.

The chimps themselves, 10 in all, are from a rescue facility for chimps who have retired from the entertainment business.