Bigger mammals usually stray more wide than smaller relative , but fossils betoken this was n’t true for extinct elephantine kangaroo . The findings could help explain the defunctness of these cracking beasts as climate change made their home ranges unviable .
Australia is famous for its existing unknown beasts , but that is nothing to what it had in the yesteryear . Compared togiant ducks of doomand3 - ton ( sort of ) wombats , giant kangaroos may seem positively normal , but they still represent an amazing feature of a lose world .
Protemnodonis an out genus of kangaroo that lived in Australia and New Guinea and grew to an estimated 170 kilograms ( 370 pound ) . Today the largest member of the kangaroo family , Osphranter rufus , average 50 kilograms ( 110 pounds ) , although some individuals reach almost twice that . SevenProtemnodonspecies are suspected , although there isstill debateas to whether some of these were really the same .
Artist’s impression ofProtemnodon. The length of its arms suggests it may have moved on all fours, rather than bounding like modern kangaroos.Image credit: Atuchin/Lawrence/Hocknull
SomeProtemnodonspecies survived in Australia until 50,000 years ago . The timing of their quenching has conduce topassionate debatesas to whether climate change or the arrival of humans bring about their demise .
The locations where we find dodo are inadequate guides to their mountain chain , since circumstances suited to preserving teeth or bones are rare . However , thesefossilscan sometimes reveal where the brute fed , because rarified element in the water system or nutrient supply become incorporated in the bones .
University of Wollongong PhD studentChristopher Laurikainen Gaetestudied the strontium isotopes inProtemnodonteeth pull together around Queensland ’s Mount Etna , whereProtemnodonwas known to live 280,000 to 500,00 years ago . He find their food supply came overwhelmingly from the local area where limestone dominates , indicating a little abode range . This , Gaete and Centennial State - authors note , was unexpected , because normally larger animals have bigger range . Certainly , the heavy survivingkangaroosbound their path across immense distances , allow them to take advantage of rainfall in arid lands .
Senior author Scott Hocknull holding aProtemnodonskull, showing just how big these got.Image credit: Scott Hocknull
From 500,000 to 280,000 years ago the climate of the sphere does not seem to have changed a raft . After that it became much more unstable .
Protemnodonspecimens are remember to have ranged in size of it from 90 to 170 kilograms ( 200 - 370 pounds ) , so their habitat might have been look to be relative . However , their skeletons advise they may have get around on all quadruplet , rather than hopping . That ’s not a entire surprise . Hopping is an exceptionally efficient method acting for get across ground , but it ’s thought there is amaximum body massbeyond which tendons ca n’t handle the jounce . It ’s plausibleProtemnodonexceeded that . Certainly , it ’s best not to take internet memes ofT. rexesbounding like kangaroos too seriously .
IfProtemnodonwas ill - suited to longsighted travel , Gaete and co - authors suspect , it might have struggled to reach new locations when climatic changes made its home ground inapplicable . Gaete state IFLScience , “ From 500,000 to 280,000 eld ago the mood of the area does not seem to have changed a lot . After that it became much more unstable . ” This would have led to periods where the rainforest that providedProtemnodon ’s nutrient was supercede by drier forests they could n’t eat .
WhyProtemnodongot so big in the first place , if it was n’t to range further , is unclear . Gaete told IFLScience it may have been as simple as being able to reach leaves on higher branch than other forest - dwellers .
The teeth on which the work was establish distinctly belonged toProtemnodon , but the exact species is uncertain . “ There was a species identified as living around Mount Etna , but a 2024 study nullified that verbal description , so we do n’t know which one this was , ” Gaete told IFLScience .
OtherProtemnodonprobably occupied dissimilar niches , allowing the genus as a whole to live until 50,000 years ago ( or possibly 12,000 in New Guinea ) . That means the debate as to whether homo happen upon the final reversal will remain . Nevertheless , it seems that a combination of preferring homelife to roaming , and a more mentally ill climate , probably made the integral genus vulnerable well before that .
The study is published open admission inPLOS One .
