Paul Adolf Krantz was appointed taxidermist at the newly established Staatsmuseum of the South African Republic (later the Transvaal Museum, now the Ditsong National Museum of Natural History), Pretoria, in 1893. Except for the honorary director, Dr H.G. Breijer*, he was the first and only employee until S.M. Tweddill* was appointed the next year. Krantz started collecting animals for the museum during the year of his appointment. He received permission to undertake a collecting expedition from May to October 1895, at his own cost, and went to an area rich in game between the Olifants and Sand Rivers in the Lowveld. Just before his departure, and again upon his return, he requested government support for establishing zoological gardens in Pretoria. The next year he went on a collecting trip in the vicinity of Lydenburg, returning in October. In January 1897 he was dismissed from his post for misconduct, but as no replacement could be found he was re-employed in April. That winter he received permission for another hunting expedition to the Olifants River, provided that the museum would have first choice in buying the animals he obtained. The expedition was successful, yielding both specimens for display and live animals for the museum's zoological garden (later the National Zoological Gardens). During these years he also collected beetles for the museum.
During the Anglo-Boer War (1899-1902) Krantz served in the Pretoria branch of the German Commando with the rank of Field Cornet. He was taken prisoner and by April 1902 was at Diyatalawa, a prisoner of war camp in Ceylon. Shortly after the war, in 1903 he was hunting big game in Mozambique for natural history purposes. By 1905 he resided in Rustenburg and offered to sell an alleged cure for east coast fever to the government of the Transvaal Colony. In July 1899 he married Martha Catharina Botha, who accompanied him during the Anglo-Boer War and was a big game hunter in her own right.