Biological Fun for the Gargolyes, West & North sides of Old City Hall of Toronto Nov 2008

Gargee: "You think I am a stone? "
Peter : "..."
Gargee: "Daytime only!!"
Peter : " !! "

Gargoyles are neither mammals, nor reptiles, nor birds.

They are part of a biological class called "gargates,"

presumably descended from the great reptiles of the Mesozoic Era or the late Paleozoic Era.

The only other known species in this group is the gargoyle beasts,

which were domesticated by gargoyles as companions millennia ago.
The most prominent biological feature of gargoyles is that

they turn to "stone" in the daytime and they are known as "stone sleep".

Suffice it to say that at sunrise gargoyles (and gargoyle beasts) turn to stone or,

to be more accurate, an organic substance similar to stone and remain that way until sunset. During this time, gargoyles sleep and dream, injuries sustained during the night heal, and they apparently absorb thermal energy from the sun's rays that gives them most of their energy.

Doctor Sevariusausom has hypothesized that without this last feature, a gargoyle would have to eat the equivalent of three cows a night in order to get airborne.
Gargoyles have a greater resistance to the cold than humans do, possibly due to a thicker skin, or hide.

Gargoyles are probably at least partly warm-blooded, especially considering their activity level in cold weather. However, because they obtain most of their energy from heat and sunlight during their sleep, they could be considered partially cold-blooded as well. Believe it or not..
Like most animals, but unlike most mammals, they lay eggs. Female gargoyles nurse their young with breastmilk.

Gargoyles do not age during their stone sleep, so they age only half as quickly as humans do. Thus, a 30-year-old gargoyle would be biologically equivalent to a 15-year-old human. A gargoyle can theoretically live to close to 200, but for centuries most gargoyles died premature deaths through being slain in battle or smashed in their stone sleep.

Gargoyles such as Hudsonsaurgyle who lived to a ripe old age were rare indeed. In modern times however, when most clans live in hiding and most humans regard them as nothing but stone statues, far fewer gargoyles die by the sword or the hammer and some - like Old Pof of the London Clan- are reaching their 190s.

Gargoyle appearance varies from clan to clan, and even gargoyles within the same clan look very different, and are usually easily told apart. Some sort of overall gargoyle anatomical norm does seem to exist, however, judging from the Scottish, Guatemalan, and Japanese clans. And many gargoyles depart from this "norm" dramatically. The London gargoyles, for example, resemble heraldic animals with feathered wings, and Zafiro of the Mayan Clan looks very much like a winged serpent, with no visible (external) hind legs. The Loch Ness gargoyles are semi-amphibious, though the details of their appearance is unknown.

Besides their shared trait of stone sleep, the most prominent gargoyle feature is the number of limbs they possess. Gargoyles are the only (living) vertebrates with more than four limbs. There are individuals like Zafiro who appear to have only four limbs, but it is possible that x-rays of Zafiro would reveal vestigial legs not visible on the exterior of his body. Gargoyles are bipedal, although they can easily run on all fours if they need to, and more or less humanoid in shape. Their wings are usually leathery, most commonly bat-like with the digits dividing the wing membrane into multiple segments , but sometimes pterodactyl-like with one continuous membrane and the digits forming a small hand atop the wing (as with Brooklyn) or web-like in the manner of a flying squirrel (as with Lexinton). However, most of the gargoyles in the London Clan, and some members of the Mayan Clan, have covering on their wings that resembles feathers.

Some gargoyles have human-like faces, such as Goliath, Demona, and Angela, while others have long snouts or beaks such as Brooklyn, and still others seem to have a sort of rounded muzzle, more simian in appearance like Broadway or Lexington. Some gargoyles have hair, while others, such as Lexington and Broadway, are bald. Hairlessness or thin hair seems to hold no significant influence on Gargoyle society or relations. Hudson's hair is gray and thinner, and has likely (if Brooklyn is any indication) always been gray. Hudson is the only living gargoyle of the Wyvern clan to exhibit facial hair, so body-hair may not be common amongst gargoyles. None of the gargoyles have been seen to shave, or indeed even groom, so the growth may take a tremendous amount of time and effort on their part.

Most if not all gargoyles have some sort of brow-ridge above the eyes in place of eyebrows, and/or horns upon their foreheads. These seem to be genetic, but they also suggest a certain amount of individual distinction. No two gargoyles have identical brow-ridges, and the ridges move with their expression, which seems to suggest they are not bone, or are covered in thick soft tissue.

Gargoyle skin color varies noticeably within a clan; for example, Goliath and Angela are both lavender, Demona sky-blue, Hudson a tan color, Brooklyn red, Lexington a sort of khaki, and Broadway turquoise. Other observed colors are teal, green, golden, tawny, orange, pink, white, pale green, and grey. Hair may be brown, white, black, yellow, or red.

All gargoyles, even web-winged types like Lexington, possess a complicated and highly refined set of additional musculature and skeletal structures above what humans identify as lateral muscles on their dorsal (back) side allowing use of their powerful wings. Their tails are prehensile, they possess enlarged canines like those of big cats, and typically have four digits adorning each limb (including their wings), though this too seems to have a degree of variance. Their major hinge joints often feature a type of spike or horn-like growth, particularly protruding from their elbows and knees, and some gargoyles' wings are adorned with these bony ornaments.

Gargoyles' arms end in hands with three clawed fingers and a fully opposable clawed thumb. Their legs are digitigrade, with hip, knee, and ankle joints fully flexible like that of a cat; they walk upright on their toes. Gargoyles refer to their feet and hands as "talons," and accurately so considering the strength they possess. In the case of their feet, they are roughly talon shaped, with three arched toes each ending in a powerful claw, and a fourth toe on each heel that points backward like that of a bird of prey, perhaps in order to provide the gargoyles with superior grip and balance even in the precarious environs of their preferred habitats.
Their wings typically feature the same configuration as their hands, with the phalanges/fingers in the wings operating similar to that of large bats, with a thumb-like structure they use to "cape" their wings, or to grip at a rough surface. Some gargoyles, such as Lexington, have no digits in the wing limb, while others, like Brooklyn, have only one digit to support the wing membrane while the others stick out somewhat like fingers of the hand. Further variances exist between particular individual gargoyles, but physical characteristics tend to share some commonality across individuals from the same clan.

Gargoyles seem to be omnivorous, but like some humans they prefer a general diet focusing on meat or fish as a primary food source. It can only be inferred from their evidence and physical appearance that gargoyles are descendants of a highly efficient, specialized group of predators. Hunting from the air would require superb eyesight (quite possibly enhanced by whatever biochemical reaction causes the glow of their eyes), sophisticated reaction times, and excellent hearing. Visual evidence suggests these attributes as well; their ears are pointed and seem to be deeper than human or simian ears, giving them greater reception of noise.
Goliath demonstrates his attenuation to his senses during his first trip through Central Park with Elisa, when he heard the subtle movements of a highly trained, highly coordinated group of special-operations mercenaries, clues that even Elisa with her police background missed. Gargoyles also seem to have a highly developed sense of smell, often using it to verify an unknown or to initially inspect an area, as Brooklyn did when first meeting Elisa; he gave two quick sniffs and then immediately questioned Goliath as to whether she was a new friend (or potentially an enemy). They seem to also use their sense of smell to steady themselves when surprised. Gargoyles will frequently inhale deeply via their noses when in deep thought, an observable trait across all gargoyles, though because of his philosophical nature, Goliath does this more often.

When gargoyles are awakening from their stone sleep or are angry, their eyes glow. In general, male gargoyles' eyes glow white, and female gargoyles' eyes glow red. Gargoyle eyes have visible irises and whites; a feature which they share with humans, but which most animals lack.
Gargoyles are immensely strong, and can actually scale stone walls, digging their claws into the stone to provide footholds for themselves. However, despite their wings, they are not capable of actual flight. They can only glide upon air currents. When gargoyles are not gliding and are on the ground, they can "cape" their wings about their shoulders which allows the beings to avoid being hindered by them as well as for the cosmetic value (with the exception of such gargoyles as Lexington, whose wings are attached to their arms). It should also be noted that, while incapable of flight per se, gargoyle wings are extremely nimble and powerful. Gargoyles on the ground use their wings as a projection of their size, often flaring their wings outward to do battle, even in confined spaces. This serves two purposes: a perceived increase in size, and an extra weapon, as gargoyles will frequently slap their enemies with their wings, or use the back of the wings as a sort of shield. They also use their wings as we use our arms, tapping objects (as Goliath did when he tapped on the camera lens in Macbeth's house) or pointing with them when it is more convenient.
Naturally, gargoyles are biologically very different from humans. Although both species are sentient and native to Earth, they cannot produce children together, short of scientific or magical intervention. Indeed, gargoyle-human pairings are almost non-existent; Goliath and Elisan's own relationship is probably one of a very few throughout the course of history.
Gargoyles are strongly in tune with the natural cycles of Earth, and there is some evidence that due to the nature of their stone sleep, they may not be capable of living off of the planet.

The funny source is from "Gargolyes Wiki"