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Description

The creatures known as Terrortubbies were purely the stuff of nightmares before the capture of live specimens replaced wild rumours with hard facts. More research has identified their prehistoric ancestors and cast light on the processes that influenced their evolution. Though gaps in the fossil record leave some room for speculation a coherent story has emerged.

Some twenty million years ago a species of small cave-dwelling bat that used radar for hunting and navigation developed bioluminescence – a trait often seen in deep-sea fish but rare in terrestrial vertebrates. As most insects are attracted to light this allowed new feeding strategies. Instead of expending energy actively pursuing prey, these more sedentary prototubbies let their meals come to them. While angler fish grew glowing lures that hung just above their mouths the prototubbies’ light sources were concentrated on their stomachs, perhaps so they could shield them and trap small creatures with their wings. Natural selection favoured individuals with larger, brighter organelles though these brought disadvantages; the fur needed for insulation dulled their luminescence and the light that attracted prey could also bring predators.

The prototubbies overcame these problems through steadily growing bigger and stronger. The fur on their bellies gave way to fine down and larger luminescent patches entirely devoid of hair. A thick layer of subcutaneous fat provided insulation and large eye spots on their foreheads intimidated enemies. Although they lost the power of flight their forelimbs grew better adapted to climbing, seizing and dismembering prey, which came to include baby birds, reptiles and smaller mammals when the prototubbies left their caves and started living in the trees.

Later prototubby species were larger, more formidable, and much more intelligent. Their well-developed nervous systems let them control the colour, tone and brightness of their light sources with more finesse than cuttlefish, and the radar once used for echolocation now allowed communication other species could not hear. Large and bulbous craniums which served as resonating chambers and natural “antenna” increased their signals’ range and strength, and together with their eye spots, changed feeding strategies once more. As dominant tree-dwelling predators, adults no longer feared eagles and owls, and ignored small animals in favour of larger game. Their high round foreheads and false faces made them seem less threatening to young primates who were drawn to the prototubbies’ sophisticated light displays, or watched in a state of hypnosis until they were seized and devoured. This approach to hunting – in which large carnivores benefit from benign physiognomy – may be unique in nature, though many harmless species use distinctive markings and behaviour to appear more dangerous and scare predators away.

The Terrortubbies of today are among the few wild animals that can survive in major cities – an impressive achievement given their size. They evidently benefit from their near-human intelligence, powers of communication, proficiency at hiding by day and moving silently at night. They mostly eat organic refuse – and the occasional lost pet – but when possible exploit the fact the average human child becomes almost immobile when staring at a glowing screen.

Description

The creatures known as Terrortubbies were purely the stuff of nightmares before the capture of live specimens replaced wild rumours with hard facts. More research has identified their prehistoric ancestors and cast light on the processes that influenced their evolution. Though gaps in the fossil record leave some room for speculation a coherent story has emerged.

Some twenty million years ago a species of small cave-dwelling bat that used radar for hunting and navigation developed bioluminescence – a trait often seen in deep-sea fish but rare in terrestrial vertebrates. As most insects are attracted to light this allowed new feeding strategies. Instead of expending energy actively pursuing prey, these more sedentary prototubbies let their meals come to them. While angler fish grew glowing lures that hung just above their mouths the prototubbies’ light sources were concentrated on their stomachs, perhaps so they could shield them and trap small creatures with their wings. Natural selection favoured individuals with larger, brighter organelles though these brought disadvantages; the fur needed for insulation dulled their luminescence and the light that attracted prey could also bring predators.

The prototubbies overcame these problems through steadily growing bigger and stronger. The fur on their bellies gave way to fine down and larger luminescent patches entirely devoid of hair. A thick layer of subcutaneous fat provided insulation and large eye spots on their foreheads intimidated enemies. Although they lost the power of flight their forelimbs grew better adapted to climbing, seizing and dismembering prey, which came to include baby birds, reptiles and smaller mammals when the prototubbies left their caves and started living in the trees.

Later prototubby species were larger, more formidable, and much more intelligent. Their well-developed nervous systems let them control the colour, tone and brightness of their light sources with more finesse than cuttlefish, and the radar once used for echolocation now allowed communication other species could not hear. Large and bulbous craniums which served as resonating chambers and natural “antenna” increased their signals’ range and strength, and together with their eye spots, changed feeding strategies once more. As dominant tree-dwelling predators, adults no longer feared eagles and owls, and ignored small animals in favour of larger game. Their high round foreheads and false faces made them seem less threatening to young primates who were drawn to the prototubbies’ sophisticated light displays, or watched in a state of hypnosis until they were seized and devoured. This approach to hunting – in which large carnivores benefit from benign physiognomy – may be unique in nature, though many harmless species use distinctive markings and behaviour to appear more dangerous and scare predators away.

The Terrortubbies of today are among the few wild animals that can survive in major cities – an impressive achievement given their size. They evidently benefit from their near-human intelligence, powers of communication, proficiency at hiding by day and moving silently at night. They mostly eat organic refuse – and the occasional lost pet – but when possible exploit the fact the average human child becomes almost immobile when staring at a glowing screen.