Three mammal species occur in Bold Park, the common brushtail possum (Trichosurus vulpecula) and two bat species, the white-striped mastiff bat (Tadorida australis) and Gould's wattled bat (Chalinolobus gouldii).
A small number of western grey kangaroos (Macropus fuliginosus) lived in the park up until 1986, when they were probably killed by dogs or vehicles.
Introduced mammal species found in the park include cats, rabbits, foxes, house mice and the black rat. Horses and domestic dogs, though not resident, are regularly exercised.
There are 28 reptile species in Bold Park. The bushland is unique in that it has all five species of burrowing snake known on the Swan Coastal Plain, one being the rare and endangered black striped snake (Vermicella colonotus).
Three frog species have been recorded: the banjo frog (Limnodynastes dorsalis), moaning frog (Heleioporus eyrei) and turtle frog (Myobatrachus gouldii).
Bold Park has a rich avifauna with 91 bird species recorded, including vagrants, migrants and nomadic species that are likely to occur sporadically.
There are three specific groups of birds which warrant special interest:
The Mount Claremont Bushland (the southerly portion of Bold Park) is the only area in Perth in which the splendid faiy-wren (Malurus splendens), variegated fairy-wren (Malurus lamberti) and white-winged fairy-wren (Malurus leucopterus) all occur together.
The second group of birds in the area of special interest are honeyeaters, which are so numerous in parts of Bold Park that the area has been known as 'Honeyeater Hill'.
There are high number of bird-of-prey species, including the Peregrine Falcon (Falco peregrinus) which is relatively rare and classified as in need of special protection. The relatively large size of Bold Park bushland is particularly important for these birds because they feed over large territories.
Over 300 invertebrate fauna have been recorded in Bold Park, including 47 ant species and 11 butterfly species.