The following represents just a small number of the unknown animals in which cryptozoologists are interested, according to Bernard Heuvelmans, "Annotated Checklist of Apparently Unknown Animals With Which Cryptozoology Is Concerned," Cryptozoology 5 (1986), extracted by Melissa Alles.

Marine Forms

Merfolk-like animals not necessarily related to the present dugong and manatees - their classical scientific explanation:

"Mermaids" and "mermen" reported from seas where no recent species of sirenians are known to have lived during historical times. In the most complete work devoted to the mermaid legend (Benwell and Waugh 1961), 70 sightings of such creatures are listed. Out of these, 52 (almost three-quarters) have allegedly occurred far from the areas where the three species of manatee, the dugong, and the enormous Steller's sea-cow are know to be or to have been confined: 47 in European waters, three off of Greenland and in the extreme northeast of North America, one in Polynesia, and one in the Arctic Ocean. In these regions, the existence of seals, sea-lions, or walruses cannot, as has been suggested, make up for the absence of sirenians, since pinnipeds lack the essential - almost indispensable - feature which makes an aquatic animal congruent with the mythical archetype of the mermaid (the devouring mother or the ever-deceiving vamp): the pectoral mammae. Only a still-unrecorded species of recent Sirenia, or possibly - though much less likely - an unknown form of primate adapted to sea-life, could explain the abundance and persistence of merfolk reports in certain seas up to modern times.

In the northern Pacific, south of the Aleutian Islands, an unidentified merfolk-like animal of much smaller size (5 feet long) observed for over two hours by naturalist Georg Wilhelm Steller in 1741, and described by him as a "sea-ape." It seemed devoid of forelimbs, and had an asymmetrical tail of which the upper fin was longer than the lower one, as is the case in sharks. Could this be the aquatic form of primate alluded to above? Roy P. Mackal suggests that this animal, which sometimes raised itself one-third of its length out of the water (as pinnipeds often do), could be either a northern form of the leopard seal (Hydrurga leptonyx), only known at present from the Antarctic Ocean, or a very young specimen of a surviving zeuglodon (Basilosaurus). The survival of this fossil archeocete could moreover account for native traditions of a large long-necked sea "monster" called tizheruk on King Island and pal rai yuk on Nunivak Island (Mackal 1980). The front flippers of both animals could have been held so closely pressed to the body as to pass unnoticed in Steller's specimen. But none of these hypotheses can explain the disturbing shark-like tail of the "sea-ape."

A marine saurian; that is, a huge ocean-dwelling reptile shaped like a crocodile or a lizard. It could be either one of the thalattosuchian crocodiles of the Mesozoic Era, which had a fish-tail and the hind-legs transformed into flippers, or a surviving mosasaurian, an outsized sea cousin of the monitor lizards. It is even possible that both of these survive separately in tropical waters.

Giant squids more than 100 and even 200 feet long overall (the largest measured specimens of Architeuthis are only about 50 feet long). Claims for much larger creatures have been conjectured from the size of scars left by the toothed suckers of large squid on the skin of sperm-whales, and from the length and thickness of the arms of squids found in the bellies of - or vomited up by - these carnivorous whales, the ratio between the dimensions of the greatest suckers and the body-length, and the ratio between the dimensions of the sessile arms and this same length being approximately constant in Architeuthis. Of course, quite differently proportioned squids of unknown genera could be responsible for both outsized sucker marks and the cession of relatively enormous arms, but this would be even more unlikely than the existence of individual specimens of Architeuthis of much bigger size, or of a larger unknown species of this genus (Heuvelmans 1958, 1968).

Freshwater Forms

In Cold Temperate Lakes and Rivers

So-called "lake monsters," generally described as the long-necked type of "sea serpent" capable of crawling on land (Megalotaria longicollis), in Loch Ness and several other Scottish locks, but also throughout the northern regions in the lakes of Wales, Ireland, Iceland, Norway, Denmark, Sweden, Finland, the Soviet Union, Japan, Canada and the U.S.A. (Costello 1974, Mackal 1980, Bord and Bord 1980). Incidentally, the Loch Ness animals have been described as Nessiteras rhombopteryx on the basis of an underwater photograph of a diamond-shaped fin (Scott and Rines 1975). This generic name is long antedated by Megalotaria (Heuvelmans 1965), but the specific name may well be retained as valid, even as just subspecific, since it is very likely that the diverse landlocked, freshwater forms differ at least slightly from the ocean-dwelling one.

"Lake monsters" similarly described, in Argentinian (iemisch?), south Australian (bunyip) and Tasmanian lakes (Heuvelmans 1955, 1958, Mackal 1980), but also in the Orange River and in the tributaries of the Vaal River (groot slang) in South Africa (Heuvelmans 1978).

Attention must be drawn to the fact that all these long-necked animals have been reported from stretches of freshwater located around isothermic lines 10°C; that is, between 0°C and 20°C (i.e., 50°F, between 32°F and 67°F) in both Northern and Southern hemispheres. One could hardly wish for better circumstantial evidence of their existence.

In Tropical Lakes, Rivers, and Swamps

In Africa (Ethiopian Region):

Giant anacondas up to 60 feet long (Sucuriju gigante) - and thus possibly belonging to a species distinct from Eunectes murinus - in the Amazon basin (Heuvelmans 1955, 1958).

A mysterious beast of the Paraguayan Chaco, described as "a slug-like snake," but as broad as a horse and having the head of a dog and a poisonous barbed spike in its stumpy tail. It is most probably what some of the local Indians call manguruyú or giant catfish, an 18-foot-long fish said to grow up to half a ton in weight (Craig 1954).

Terrestrial Forms

In Europe (Palearctic Region):

Wild hairy men, most probably Neanderthals having survived into historical times. Know as satyrs in classical antiquity - a name borrowed from the Hebrew se'ir ("the hairy one") - and as wudewása ("wood being") in the Middle Ages, they were reported until the 13th century in Ireland, until the 16th century in Saxony and Norway, until the 18th century on the Swedish island of Öland and in Estonia, in the Pyrénées (iretges, basajaun) up to 1774 at least, and in the Carpathians ("wild man" of Kronstadt) up to 1784 at least.

In Cold Temperate Asia (Palearctic Region):

Gigantic hairy hominoids (most probably Gigantopithecus sp.) in southern Tibet (nyalmo, mi-chen-po), Sikkim and northern Bangladesh, from where, like the Neanderthal-like men, they spread into the Oriental Region, namely Burma (tok, kung-lu), China up to Manchuria (xiao, da-mao-ren), and North Vietnam (shan-tu).

Mammoths (Elephas primigenius) allegedly surviving in Siberia's taiga, an endless evergreen forest of pine and birch. The age-old rumors claiming their survival seem to be based mainly upon specimens frozen from between 9,000 and 13,000 years B.P., complete with muscles, skin, and hair. These impressive carcasses have occasionally been seen "emerging" from blocks of melting peat by terrified natives. There is only one detailed report of an actual encounter with a live animal: an elderly hunter born in the Usuri region told a French consul in 1918 that, two years before, he had sighted a huge elephant with very curved tusks and fairly long hair after having followed its enormous tracks in the woods for several days. Although perfectly matter-of-fact and ingenuous, this story is so vaguely and even absurdly located that it is considered far from reliable (Heuvelmans 1958).

In North Africa (Palearctic Region):

Very large snakes reported from eastern Morocco to Tunisia, and often said to be longhaired (crested, or, much more likely, seen shedding their skins). They could be pythons surviving - just as crocodiles have - in scraps of tropical vegetation remaining north of the Sahara Desert, and occasionally straying from them (Heuvelmans 1978).

In Tropical Asia (Oriental Region):

Giant bats, said to be the size of a small child, reported from Vietnam, Java (aul), and the Philippines.

A youth-sized ape with a conical head, reported since classical antiquity ("Pan with wedge-shaped head") and now sensationalized as the abominable Snowman, in northern India and the Himalayas, from Kashmir (vana-ma-nusha) to Bhutan (jungli admi), through Nepal (yeh-teh or yeti, mi-teh), Sikkim (shukpa) and Bangladesh (ban-manush). It has long been confused with both the Neanderthal-like men and the Gigantopithecus-like hominoids mentioned above, but it is obviously a true ape, running on all fours when hurried (Izzard 1955). It is probably a remnant of the rich fossil pongid fauna of the Siwaliks, which includes Sivapithecus. It has been described as Dinanthropoides nivalis (Heuvelmans 1958). While it is quite possible that the fossil anthropoid apes referred to above are more closely related to this form than to the orangutan, it is equally possible that the so-called Snowman is merely a particular form of orangutan, more terrestrial than the tree-dwelling kind.

In Tropical and Southern Africa (Ethiopian Region):

An alleged bear of unparalleled ferocity in East Africa (chemisit, ketit, shivuverre, koddoelo, Nandi Bear). Reports are often based upon sightings of very large black ratels or honey-badgers (Mellivora capensis), and upon the savage deeds of spotted hyenas of unusual color or size, but probably also, originally, upon encounters with gigantic baboons supposedly extinct (Theropithecus [Simopithecus] sp.) (Heuvelmans 1982).

Flying lizard-like animals reminiscent of the pterosaurs of the Mesozoic Era, in Zimbabwe and Zambia (kongamato), around Mounts Kenya and Meru in East Africa, in the Kasai Province of Zaire, in Cameroons (olitiau, an obvious misunderstanding for ole ntya, "the forked-one," i.e., the Christian devil), and in Ghana (sasabonsam). Some of these could actually be unknown species of giant bats, or even the strange-looking hammer-headed bat (Hypsignathus monstrosus) (Heuvelmans 1978).

Rather large snakes, said to be crested and often to have a cry like the crow of a rooster, reported throughout tropical Africa. They are know as n'gôk-wiki to the Baya of the Central African Republic (Heuvelmans 1978). Described as truly gigantic in the Mataba River area, in the norhtern Congo, where they are know as nguma-monene (great snake), similar reptiles with a serrated ridge running along the spine could, according to Roy P. Mackal, be outsized monitor lizards, or even more primitive snake-like lizards (Mackal 1986).

In North America (Nearctic Region):

Gigantic, hairy hominoids, leaving huge human-like footprints, some showing distinct dermatoglyphs, reported from most Canadian provinces and American states, from Alaska to Florida, but more frequently from those bordering the west coast of the continent (sasquatch, oh-mah, toké-mussi, Bigfoot) (Sprague and Krantz 1977, Green 1978, Bord and Bord 1982). This form, generally thought to be related to the fossil gigantopithecines of Asia, Gigantopithecus blacki of China and Gigantopithecus bilaspurensis of India, has, in fact, been formally assigned to Gigantopithecus blacki by Grover S. Krantz (1986). Krantz has also proposed that, should the living form prove to be sufficiently different, Gigantanthropus canadensis would be an appropriate name.

A chimpanzee-like ape, mainly nocturnal and capable of swimming, reported from North American swamps and in temperate bottomland hollows. It is probably the same creature which is known as bukwus to the Tsimshian Indians, and after which they carved wooden masks. Despite its smaller size and its quite different habits, it has generally been confused with the former hairy giants. According to Loren Coleman, it could be a Nearctic representative of the dryopithecines, believed until now to have been restricted to the Old World from the Miocene to the Pleistocene (Coleman 1983).

Gigantic flying birds of prey, with a wingspan of between 10 and 16 feet, and thus larger than the Andean Condor. Generally dubbed "thunderbirds," they are suspected of attempts to abduct small children, and have been reported from innumerable parts of the southern half of the USA. Loren Coleman suggests that they could be North American teratorns surviving from the Pleistocene. The most common of them, Teratornis merriami, had a wingspan of 10 to 12 feet, and Teratornis incredibilis, from Nevada and California, may have approached 17 feet. Some of the remains of these huge carnivorous birds are only 8,000 years old: it seems that they were hunted by early Amerindians (Coleman 1985).

Outsized lizards, snakes, beavers, and even kangaroos - not to mention dinosaurs, unicorns, and flying men - reported from many parts of the USA, but obviously based in most instances upon misidentifications, gross exaggeration, or plain hoaxes.

In Australasia (Australasian Region):

Gigantic monitor lizards, up to 30 feet in length, reported from tropical rivers and lakes of eastern Australia, but also reported in scrub-covered mountain ranges of New South Wales, around the Murray River, and even further south near Lake Alexandrina in Victoria.

Small, dark men, with long straight hair on their heads, and sometimes slanderously said to be endowed with the Christian devil's attributes, such as a tail and goat's feet (vui, wui), on some of the New Hebrides islands.