Qaisracetus is an extinct protocetid early whale known from the Eocene (Lutetian, 48.6 to 40.4 million years ago) of Baluchistan, Pakistan (31°00′N 70°12′E / 31.0°N 70.2°E / 31.0; 70.2, paleocoordinates 12°24′N 65°42′E / 12.4°N 65.7°E / 12.4; 65.7).

[3] "Qaisra" is also etymologically close to the royal title used in Persian and many Indo-European languages (e.g. Kaiser, Czar, Caesar).

[7] Qaisracetus has a generalized protocetid skull with the external nares located relatively anteriorly (above C1) and a relatively broad frontal shield.

The sacral morphology of Rodhocetus and Qaisracetus indicate protocetids represent a wide range of specializations, although which is ancestral to later whales is unclear.

[7] Because of similarities in its dental microwear patterns to those of present-day orcas and hyenas, Q. arifi is believed to have eaten other marine mammals.