| 1 | Japanese ratsnake |
The longest snake on the Japanese mainland, averaging at 1-1.8 metres. Japanese ratsnakes are non-venomous and mainly prey on warm-blooded prey like mammals and nesting birds. However, they also have the ability to eat eggs, an ability they happily exploit.
The Japanese ratsnake slithers up to eggs in bird nests and seizes them with their fangs. The next step is 2 minutes of laborious rearranging, to ensure that the narrower end is pointing inwards. Then they swallow the egg whole, and wriggle it to a spot approximately 6-8 inches from their mouth. The egg is still unfractured, but this is when the species’ specially modified spine comes into play. A Japanese ratsnake has vertebral shelves which are elongated, to create sharp hypapophyses, each of which is capped with enamel.
When the ratsnake contracts its body, egg still inside, these act as instant puncturing tools, causing the yolk and contents to leak while inside the snake’s belly. The ratsnake then enjoys all the vitamins and minerals within. Japanese ratsnakes get faster at eating eggs with repetition; one study found that the first egg took 20 minutes to swallow, followed by 7 minutes thereafter. Young ones lack the specially sharpened spine, so it’s mainly adults that are the egg-swallowers.
| 2 | Taiwan kukri snake |
A resident of Taiwan, China and far southern Japan, which is non-venomous and lives in lower mountainous areas and plantations. Rather than swallowing and crushing, Taiwan kukri snakes (Oligodon formosanus) do their work beforehand. Their maxillary teeth are brutally sharp and thin, and they use these to make repeated slashes in the eggs’ leathery surface. With persistence, the shell breaks, and the golden yolk begins to dribble out. The Taiwan kukri snake then thrusts its head inside the broken egg and slurps up the treasure within. This species is able to displace its maxillary bone, allowing it to hold and slash at the same time.
Being an egg lover, one of their favourite foods in captivity is chicken egg yolk, which they grab from the hands of keepers ravenously. In the wild, they eat many bird eggs, but particularly love green sea turtle (Chelonia mydas) eggs.
These sharp teeth also make them a handful for people, despite measuring just 0.5 metres. Picking up a Taiwan kukri snake can trigger a lightning storm of razor sharp, slashing bites. Generally, kukri snakes will flee when they encounter a human, although not particularly quickly.
| 3 | Sibon argus |
This 40cm species has two names: Argus goo eater or Argus snail sucker. The latter is because of their ability to suck slimy snails from their shells, but the former is because they love to scoop up orange frog spawn and swallow it.
Argus goo eaters mainly live in eastern Panama and southeastern Costa Rica. They’re a jungle snake which lives on branches and large leaves, and next to small streams where their frog spawn dinner accumulates. Their strategy is to wrap their tails around tree branches, then dangle their heads down to lower branches and swallow up eggs laid in moss clumps or leaf undersides. They also slither directly along branches in fine balance. Argus goo eaters can be a messy eater, ending up with frog spawn all around their mouths like a baby needing a bib. Research is lacking, but they’re confirmed to eat the spawn of emerald glass frogs.
Rather than snails, frog spawn seems to be the main prey of Argus goo eaters. When chytid fungus infested the one region of Panama and decimated the native frog population by 75%, the local Argus goo-eaters also plummeted. Meanwhile, the more generalist eyelash viper was barely affected.
| 4 | Indian egg-eating snake |
An Indian snake measuring 40-60cm, which mostly lives on the ground, but climbs thin vegetation with ease. This species has large protruding eyes, a pale blue belly, and black scales with a yellow stripe running down its spine.
Indian egg-eating snakes are hardly ever seen, but are believed to be common nevertheless. It’s their nocturnal habits and love of hiding in crevices that help them escape peoples’ eyes. Like Japanese ratsnakes, Indian egg-eating snakes swallow eggs whole and then crack them apart, using similar hypapophyses attached to their spinal column.
The eating process was observed in detail in 2014, after being gifted two blue rock pigeon eggs, which the snake greedily gobbled up. The snake squeezed the egg to its cervical region, but then stayed still for 3 minutes. Suddenly, it thrust its lower body downwards with massive force, to crack apart the egg inside with a single blow. Then it kept up the massaging pressure with horizonal writhing, with each contraction lasting 2 seconds, to push the egg’s contents towards its stomach. The snake then regurgitated the shell. From swallowing the egg to the finish, the process took 56 minutes.
| 5 | Blanford’s bridle snake |
Blandford’s bridle snake is one of dozens of harmless snakes that quietly go about their business in the forests of southeast Asia without an ounce of attention from mankind. It’s in the same family as the Indian wolf snake (Lycodon aulicus), and has been observed in almost all regions of Thailand. Blanford’s bridle snake was previously thought to eat geckos, but a 2020 study revealed that they ate bird eggs exclusively. These included puff-throated bulbul, Abbott’s babbler, and white-rumped shama eggs.
The study was a big one, covering 7 years (2013-2019), 23 different species, and 478 nests in total. Blandford’s bridal snake turned out to be the third most important bird nest predator of any animal, not just among snakes. The species accounted for 13% of nest raidings, and for certain species they particularly favour, the total was probably higher.
The bridal snakes spent an average of 81 minutes at each nest. They turned out to be a strictly nocturnal snake, with only one snake spotted eating eggs before sunset. Blanford’s bridle snake (Lycodon davisonii) was more flexible than some, as they usually swallowed the eggs whole, but sometimes carved openings in the shell and slurped out the insides.
| 6 | Central African egg-eating snake |
This might be the most adapted egg-eating snake on Earth. The Central African egg-eating snake, AKA Dasypeltis fasciata, eats eggs exclusively. Like other Daspypeltis members, this is a tree dwelling species. Its world consists entirely of branches – branches to sleep on, branches to use as pathways, branches where nests might be balanced.
Dasypeltis fasciata hunts at night, to take advantage of birds which leave their nests unguarded by day. They’re one of the egg eaters which swallows them whole, before crushing them with enlarged vertebra. But Dasypeltis fasciata goes beyond the Japanese ratsnake in having a particularly sharp sense of smell, allowing them to distinguish between a fresh egg and a rotten one which is too far gone.
They even have a specially adapted trachea, which allows them to roll a bowling ball-sized egg around their mouths and breathe comfortably at the same time. Their mouth is toothless, allowing the eggs easier access. The only trouble is that this reduces their ability to defend themselves. Instead, Dasypeltis fasciata uses Batesian mimicry, disguising itself as venomous snakes. This species is thriving in the wild, as they have very little competition for their staple food source.
| 7 | Black-collared snake |
This Amazon rainforest snake is known to only a handful of Westerners, yet lives in a huge range in South America, from French Guiana to Peru to Bolivia. It’s the sole member of its family, hence its Latin name Drepanoides anomalus. A glance at a photo reveals a black collar, white belly, and coral red scales on its body. It’s a semi tree dwelling species which mainly lives in forests, and tends to flee if approached by humans, and only thrash violently if picked up.
The black-collared snake often falls victim to other snakes, including the dreaded clelia clelia, and most of its own diet consists of lizard eggs. Research is thin, but eggs have been found in the stomachs of black-collared snakes from Peru, Ecuador, and Brazil. One study reached a verdict of 70% lizard eggs, and the species also eats other snakes, including brown-banded watersnakes. Black-collared snakes are primarily ground dwelling, but climb with ease, and can sometimes reach 3 metres in the air.
| 8 | Scarlet snake |
This 40-60cm Floridian snake is particularly obsessed with turtle eggs. Scarlet snakes are non-venomous, but have brutally long front teeth. These go to the purpose of hacking through tough shells.
A scarlet snake’s strategy is first to locate the turtle’s special burrow. Then they’ll slither into the dark chamber and wrap around the first egg they see. With their coils tightly in place, the scarlet snake swings its head down to force its fangs deep into the shell. Without removing the fangs, the scarlet snake squeezes with its body, thus forcing the nutritious yolk and white into its open mouth. The loggerhead sea turtle is one species whose eggs they’re confirmed to hunt.
Scarlet snakes also devour eggs with pleasure in captivity. Because of this diet, scarlet snakes have evolved far longer front teeth than some venomous snakes, including the pygmy rattlesnake. Fortunately, they never use these against people when picked up. Scarlet snakes are very shy, and mainly live in hardwood forests, beneath a mixture of rotting logs and leaves.
| 9 | Eastern fox snake |
A semi-endangered species of the northeast USA and Canada. Eastern foxsnakes are related to corn snakes, and have strict habitat preferences. They dislike forests and heavy agriculture, and stick to dry open areas or marshland. They consume a long list of bird eggs, including pheasant, duck, pigeon, and quail eggs. They particularly love sparrow eggs, including house sparrows, chipping sparrows, and song sparrows.
The exact mechanism behind their egg crushing isn’t known, but they swallow them without any coils, and crush them somewhere in their long body (one old report said the throat). Eastern foxsnakes like to frighten mother birds away from their nests, then dash in and swallow the eggs they’ve left behind. They also invade chicken coops, so that shocked owners see a tail poking out of one end. After swallowing the egg, they later spit out the useless shell fragments. However, foxsnakes sometimes have the tables turned on them; a 2011 report confirmed that American badgers eat their eggs.
| 10 | Puffing snake |
This South American snake is non-venomous, but hisses loudly when confronted, before inflating its neck and delivering a sharp bite. Locals have long spoken of its nest raiding habits, and science has recently confirmed it.
A 2005 study examined spotted antbirds and chestnut-backed antbirds, monitoring their nests for dozens of hours using videocameras. 10 nests were raided for eggs, and the puffing snake accounted for 8 of those. A 2015 study tested the chestnut-backed antbird again (they seem to love this family). This time, the puffing snake accounted for 37 of 46 egg thefts.
Puffing snakes are crushers, using the common method of swallowing, then writhing to burst the egg while inside them. This species flexes its body from front to end, like a rope being tightened. When forcing the eggs further down their body, they move their snout from left to right. One guy spotted a northern puffing snake (Phrynonax polylepis) raiding a great tinamou nest. This ground bird has bright turquoise eggs, and when the snake forced the whole egg into the core of its body, the neon colour was still visible through its scales. The two common species, P. polyepsis and P. poecilonotus, are closely related and have many egg theft records to their name. Unlike some, puffing snakes eat both eggs and the recently hatched nestlings.