Restricted or enabled only by the bounds of natural selection, nature has proven that a vacuum is hard to maintain. While some types of creatures might seem fit for science fiction or simply defy our imagination, the natural world holds a place for creatures that defy common sense or human expectation in existing. Discover poisonous birds, freshwater sharks, plant-eating spiders, and other animals that just don’t seem right, but are out there waiting to expand your concept of life.
10. Pitohuis, the Poison Birds of New Guinea
A bird is the last thing to come to mind when we think of poisonous animals, but the different species of Pitohui from New Guinea are toxic feathered beauties from the rainforest, to be approached with great care. A poisonous bird: What will they think of next? Native to the rainforest environments of New Guinea, the Hooded Pitohui is correctly termed as a poisonous species, rather than a venomous species as a highly dangerous batrachotoxin is present throughout the bird’s feathers, skin and flesh. The bird’s toxicity became apparent in 1989 when a California Academy of Sciences based researcher named Jack Dumbacher who had set out to study birds of paradise in Papua New Guinea noticed burning pain in his hands when scratched by the peculiar Pitohuis caught in nets originally intended to catch birds of paradise for closer inspection.
The toxins that make up the chemical arsenal of these birds are in fact the same lethal compounds found in poison dart frogs notorious for being capable of killing predators and humans alike. Exactly why the birds possess this toxicity remains a matter of scientific interest, with associated speculation that the bright colors of these birds warns potential predators of their chemical laden bodies. The process by which pitohui toxins concentrate also formed a subject of scientific curiosity that was solved by Dumbacher when he went back to the rainforest and in collaboration with locals was able to determine that the source of the toxins consisted of poison-bearing beetles that the birds consumed in quantity.
9. Ocean Lizards
Lizards represent the hot desert in the minds of most people to a great degree, or at least a sunny, perhaps dusty garden path or tree trunk in a warm tropical jungle. Yet, a member of this vast and diverse group of small dinosaur lookalikes has done the unimaginable and become marine, basking on wave splashed rocks and foraging under the surf. Native to the Galapagos Islands and surrounding waters, the large and colorful Marine Iguana is a lizard that has mastered the sea, hauling out on rocks like a sea lion in between dives below the waves, where they forage on marine algae and seaweeds chewed off the surface of submerged rocks.
The plant-based diet is easily harvested with the help of the iguana’s razor like teeth. Efficiency is key to Marine Iguana survival, as meals must be gathered quickly to prevent chilling and loss of heat energy. Measuring over 3 feet in length and weighing up to 22 pounds, the Marine Iguana is the only ocean-going lizard on the planet. Large groups of breeding females jockey for space in the breeding season, while males fight fiercely for a chance to mate with the female of their choice. The dinosaur-like creatures are normally blackish or greyish in color, but the males stand out with its greenish and reddish hues that come into color during the breeding season, signalling dominance and urging females to select them as mates.
8. Freshwater Sharks
Freshwater might seem like a place to swim safely without fear of sharks, but a population of Bull Sharks, a species known to have caused human deaths lives in Lake Nicaragua, while several species of river shark patrol fast moving waters in parts of Asia and Oceania, including Australia. Bull Sharks are a primarily ocean going species, but a population oddly yet naturally established in Lake Nicaragua ensures that swimming in a lake is not a guarantee of safety from shark attacks. While normal marine bull sharks are known to travel temporarily up rivers, the true river sharks belonging to the genus Glyphis are rare, at risk species characteristic of rivers and in some species, estuarine waters.
The Ganges Shark is the most closely associated with river habitats, while the Northern River shark and Spear-toothed Shark inhabit rivers and estuaries but more frequently swim in marine coastal zones. While the degree to which they travel in saltwater varies, what these sharks have in common is complete mastery of freshwater environments, with the Ganges shark being especially comfortable far upstream from any source of saltwater. The Bull Sharks that inhabit Lake Nicaragua are not a separate species, but as a population have admirably adapted to the purely freshwater environment of the lake. In order to survive, they draw upon their ability to excrete urine at a higher rate than normal to allow proper osmosis in their lifelong freshwater environment.
7. Meat-Eating Parrots
The Kea of New Zealand is an endangered parrot that acts like a hawk or vulture, eating the young of shearwater chicks and scavenging mammal carcasses. Superficially cute and cartoonish with huge “gooey” eyes, the Kea is the only alpine species of parrot in the world, able to handle cold winds, snow and low temperatures for prolonged periods of time. Their physical adaptations include the ability to soar like a raptor, effectively insulating, thick feathers and exceptionally sharp, hooked beaks that make them adept opportunistic harvesters of meat. Attacks on live mammals are also known to have occurred, especially presenting a concern in the context of livestock management.
Because of the tendency for Kea to sometimes prey on vulnerable sheep, wounding them and removing fat and tissue with their sharp bills, a bounty was placed on the birds, which are now protected but still classed as vulnerable. When not feeding on meat from carrion or live prey or searching for plant material, Kea may use their scythe-like bills to extract juicy grubs from the soil, drawing upon their high quantities of nourish fat and proteins. Brown and green in color at rest, the Keas may seem disappointingly dull to first time observers searching for these parrots, but offer a surprise when viewed in flight from beneath with their bright red wing linings and graceful maneuvers as they search for their next meal.
6. Bipedal Antelopes
Humans might have a near monopoly on mammalian bipedalism and antelopes seem to be the very definition of a quadruped. Yet, the slender Gerenuk, with a name that originates from the Somali word for “Giraffe-necked” defies ungulate normality as an antelope species that feeds in bipedal mode. The silhouette of the species is unique among all mammals, crossing a stretched version of the typical ungulate body with an almost primate like-vertical stance. While Gerenuk feeds, the front legs awkwardly extend forward into the air. Standing on its spindly hindlegs to reach heights of almost 8 feet, this near threatened ungulate presents a bizarre sight in the grasslands of East Africa, browsing on leaves, berries, buds and flowers that other species cannot reach, especially Acacia leaves.
The ability to stand upright adds to the Gerenuk’s already long legs and almost ridiculous looking, lengthened, skinny neck in allowing them to reach edible plant material well beyond the reach of most other antelope species, from which they also derive most of their water. With the remarkable occurrence of bipedalism in a hoofed mammal species attracting scientific curiosity, investigation into Gerenuk physiology has revealed interesting adaptations that facilitate and indicate significant evolutionary commitment to bipedal capabilities in this species. Specifically, Gerenuks have smaller lumbar spinal protrusions, known as processes, allowing increased inward curvature of the spine required to stand upright for prolonged periods of time.
5. Lake Seals
A freshwater seal species does exist and it defies the very definition of marine mammal by it’s entirely lake bound occurrence. Known locally as the Nerpa and possibly half a million years old as a species, the Baikal Seal is the only true entirely freshwater seal species on the planet, restricted to the deep and mysterious Lake Baikal, which is in fact the deepest lake on Earth. Relying on the strange looking Baikal Oilfish or Golomyankas for the majority of their diet as well as sculpins and amphipods, these aquatic carnivores are a species of uncertain origin, still presenting a mystery to biologists who have yet to precisely pin down the circumstances leading up to their establishment in the lake as an endemic species.
Lake Baikal is not only extraordinarily deep, it is also extremely cold, with ice that remains into the spring breeding season. Well adapted to their environment, female Baikal Seals have developed the ability to create ice dens, in which they take shelter and subsequently give birth, usually to one pup. A small seal, the Baikal Seal may reach just past 4.5 feet in length and weigh no more than 154 pounds in most cases. The gray colored, docile lake seals maintain breathing holes in the ice and haul out along rocky shorelines in warmer weather.
4. Plant-Eating Spiders
The concept of a plant-eating spider is something that is unlikely to have entered the minds of most people. The reality that a herbivorous spider exists is likely to surprise even many who are trained biologists or biologists in training. Residing in Southern Mexico and Central America, the recently discovered jumping spider species Bagheera kiplingi is a huge eyed, rather cute looking arachnid that lives a lifestyle running completely counter to what we generally would expect of spiders. The very epitome of a carnivorous invertebrate, spiders are notorious for trapping their prey in webs, ambushing animals from tunnels, injecting doses of venom that are sometimes strong enough to kill a human and running down small prey on foot.
In contrast, the primary component of the diet of the brown and white jumping spider Bagheera kiplingi consists of Beltian bodies, tiny, fibre-rich parcels of plant material that provide certain Acacia plants with the resources to engage in a mutually beneficial relationship with ants that feed on the Beltian bodies but defend the tree from plant eaters. The enterprising Bagheera kipling, however, feeds on the Beltian bodies “intended” for the ants, while avoiding attack by the ants through what might be termed mock predation, swiftly lunging for the Beltian bodies and then beats a hasty retreat from the advancing ants. The spiders are mostly herbivorous, but at times may feed on ant larvae.
3. Nocturnal Gulls
The owls might be the first and only category of birds recalled when nocturnal avian species are brought up. Yet, a little known and unlikely marine bird from the Galapagos Islands, Ecuador and Malpeno Island, Colombia has fully mastered the night sky through an incredibly strange detour in evolutionary history. Foraging above the moonlit waves, the Swallow-tailed Gull sees in the relative darkness well enough to navigate and capture their fish and squid prey by moonlight, resting and tending to the young by day.
With ghostly pale spots on its plumage, a dark head and fleshy red tissue circling the eye, the Swallow-tailed Gull is the only truly nocturnal seabird on the planet. The strange looking gulls are equipped with extra large, darkened eyes containing a layer of reflective tissue that bounces light back through the retina to the bird’s photoreceptor cells, aiding it in seeing well while hunting at night. Biochemical adaptations include reduced melatonin levels, a sleep inducing hormone found in higher quantities in all other gulls. Heading out at night in large flocks, the night gulls swoop down to seize squid, small fish and any other invertebrates in reach in their prominently hooked bill before returning to their nesting colonies.
2. Fishing Cats
It is a well established fact in the minds of most that cats detest water, yet there is a species of feline from Asia so committed to an aquatic lifestyle that dramatic physical adaptations have defined its evolutionary history. Instead of shying away from water, the appropriately named Fishing Cat from South Asia and Southeast Asia inhabits wetlands, mangrove swamps and the edges of rivers and streams where they hunt for fish, catching aquatic prey with their sharp claws or seizing prey in their teeth during opportunistic dives into watery feeding areas.
Not afraid of water, the cats have a variety of physical adaptations that give them mastery of the water as some of the most skilled swimmers among predatory mammals. Fish eating cats have short tails, powerful muscles and the ability to walk in mud without sinking and excellent paddling and diving ability, allowing them to plunge deep into the water to capture fish, which forms the major portion of their diet. A thick, short fur base layer of fur insulates the cats from wet and cold when in the water, while longer hairs provide camouflage. An underwater surprise attack approach to hunting waterfowl, where the cats grab swimming birds by the feet from below has also been reported and ranks among the eeriest ways that a mammal can hunt birds.
1. Vegetarian Vultures
Vultures are the quintessential carrion scavenger and often carry a distasteful association with death in human minds. Yet, a quirky vulture widely distributed across sub-Saharan Africa stands out in total rebellion against vulture ways. Through yet another unlikely and incredibly specific jog in the evolutionary history of modern fauna, the appropriately monikered Palm-nut Vulture has adapted to a diet centered primarily upon plant material, focusing its foraging on the fruits of the Kosi Palm, Date Palm and Acacia. To feed, the Palm-nut Vulture opens the kernels before extracting the nutritious, fatty meal inside each palm kernel utilizes its massive bill to crack fearsome beak to break open its palm kernel “prey” and strip fruit flesh.
At just two feet long, with a wingspan under five feet wide, the black and white bird with bright fleshy facial patches is actually the smallest Old World vulture species in the world. The plant eating raptor’s small size and agility, coupled with talon bearing, powerful feet facilitate its impressive foraging gymnastics, where it hangs upside down like monkey from palm branches, accessing its food. The entirely vegetarian source of protein forms the bulk of the natural food supply for this bizarre bird of prey, up to 92 percent of the juvenile diet and 58-65 percent of the diet of adults. Fish, insects and occasionally, bats supplement the palm nut, fruit and seed diet of this bird.