If Satan were a Yukkuri... Satan: "Welcome to your eternal damnation to...what are you doing to Mister Braids? Shtop it, eajy! Yunyaaa, let Shatan take it eajy! Yunyaaaaaaaaaaaa!!" Me: "Happiness!"
Became a cannibal on Monday, Raped Marisa on Tuesday, Stole a house on Wednesday, Took a shit on Thursday, Gave birth on Friday, Pissed off a store clerk on Saturday, Died on a Sunday.
Its hard to believe that anyone would think that yukkuri could become overpopulated. Considering there many weakness, only clever and/or luck yukkuri would live to complete a life cycle
Unfortunately, most of the artists agree that yukkuris breed at fast rates and that there are plenty of them around. There's so many of them, they don't need to complete a life cycle.
Yes, that. Many of the stories - illustrated or otherwise - have yukkuri growing being born two or three days after a mating (and usually in litters of four or more), then growing from infancy to mating-capable adulthood within a week of birth. They suck at killing and eating most other species of animal, but almost all plant life is defenseless against them, and plant life is the backbone of all land-based ecosystems.
Left to breed and grow unchecked, they can (and, again, in most stories -will-) devastate an entire region's plant life in a year or two following the first introduction of a breeding pair to the region.
I've always thought that by the time a family gets abused and smashed in a story, they'd already have had the chance to produce several litters worth of more yukkuris already.