The brothers are shown in trophy photos standing next to a dead elephant, crocodile, kudu, leopard and waterbuck.
The animals were all shot on a hunting range close to Zimbabwe's Victoria Falls. In one picture, Donald jnr is holding a knife and a severed elephant tail.
Wealthy hunters pay thousands of dollars to shoot big game in Africa. The most prized hunts are the so-called "Big Five" - leopard, lion, rhino, elephant and buffalo. Four of the five are endangered. Killing one can cost US$10,000 ($12,400) for licences, which are meant to be strictly rationed.
Hunting lodges insist animal populations need to be controlled and that money generated through licences finances conservation efforts and provides employment.
In a series of tweets, 34-year-old Donald jnr defended his holiday: "I hunt and eat game. I am a hunter, I don't hide from that." He also denied that the kills were wasteful, writing: "I can assure you it was not wasteful. The villagers were so happy for the meat which they don't often get to eat. Very grateful."
But many conservation groups are uncomfortable with private hunts, especially in Zimbabwe, where endemic corruption and a poor security situation means poaching and overkill are rampant. One conservationist said private hunting should be banned for two years until a count of the country's animals was made.
- Independent