Randow collected numerous native species such as tufted grey langur, purple-faced langur, toque macaque, sloth bear, Sri Lankan leopard, Asian water monitor, axis deer and sambar deer and other Asian species like; Asiatic black bear, Bengal tiger, Malayan tiger, Malayan tapir, rhesus macaque, bonnet macaque, a variety of pythons, fish and invertebrates.

Although Dehiwala Zoo officially began operating in 1939, an impressive animal collection already existed as part of the Hagenback company's holding area where the public could visit.

Lyn de Alwis was able to acquire several rare species for the zoo like; Western gorilla, clouded leopard, red panda, Kodiak bear, North China leopard, Chinese mountain cat, Oriental stork and Chinese giant salamander.

The diversity of the zoo is shown its in aquarium, two walk-through aviaries, reptile house, butterfly garden and many enclosures of varying sizes.

To provide more natural habitats some lawns of the Zoo have been converted into small forest patches which are rich in rare plants.

The zoo consists of shaded pathways with arched cemented bridges for crossing animal enclosures although other equally attractive alternatives exist.

The museum section displays animal remains such as skeletons, footprints, eggs, excrements and specimen as well as preserved mammals and birds.

Educational programme on chimps One of the main attractions of the Dehiwala Zoo is the baby chimpanzee Sanju.

The zoo consists of diverse indigenous species as well as foreign wildlife including mammals, reptiles, birds and fish, destined for a horrible and torturous time spent.

The zoo currently houses many different species of mammals including Sri Lankan elephant, lion, jaguar, tiger, sloth bear, brown bear, rusty-spotted cat, Sumatran orangutan, common chimpanzee, lar gibbon, Hamadryas baboon, ring-tailed lemur, silvery lutung, purple-faced leaf monkey, Chapman's zebra, Przewalski's horse, eastern black rhinoceros, reticulated giraffe, hippopotamus, pygmy hippopotamus, Arabian oryx, scimitar-horned oryx and nilgai.

These exhibits house a large array of birds including spot-billed pelican, white-bellied sea eagle, emu, ostrich, southern cassowary, macaws, owls, great argus, scarlet ibis, Victoria crowned pigeon, mute swan, Malabar pied hornbill, Sri Lankan grey hornbill, violet turaco, green turaco, red-crested turaco and southern hill myna.

They have been able to breed; Pygmy Hippos, Common Hippopotamus, Eastern Black Rhinoceros, Chapman's Zebra, Przewalski's Horses, Reticulated Giraffes, Arabian Oryx, Scimitar-horned Oryx, Lar gibbons, Sumatran Orangutans, Silvery lutung and Bengal tigers.