Flo’s Little Brain - The Fossil Chronicles - page 121

Weidenreich noted with some puzzlement that the RBS of dwarfed wild
dogs, rather than being larger, was approximately the same as that of
larger wild dogs . 27 A former student in my laboratory, Angela Schauber,
found the same thing when she compared RBS in mainland foxes and
their dwarfed cousins that live on a few isolated islands of the coast of
Southern California.
Another clue came from a 2009 study by British paleontologists
Eleanor Weston and Adrian Lister, who examined the RBS in two spe-
cies of extinct dwarf hippopotamus from the island of Madagascar . 28
Weston and Lister used a larger African species of living hippo to model
the extinct dwarfs' nearest mainland relative. The cranial capacities
for the dwarfs turned out to be as much as 30 percent smaller than
those of mainland hippos after body sizes had been taken into account,
which violates the traditional scaling principles discussed above. The
authors also reviewed similar findings for island-living dwarfed bovids
(cloven-hoofed mammals) and elephants. Weston and Lister suggested
that the reason brain size was able to evolve independently of body size
on islands is that brain tissue is energetically expensive to grow and
maintain, and a decrease in its volume may therefore have been advan-
tageous for survival in environments with limited resources. 29
These exciting findings about RBS in hippopotamuses clearly chal-
lenge current understanding of brain-body scaling in mammals and
suggest that the process of dwarfism might account for the small brain
size of Hobbit. 30 However, although the dwarfed Homo erectus hypothesis
regarding Homo floresiensis is a distinct possibility (take another look at
figure 17), we can by no means be certain that it is the correct scenario.
I shall return to this controversial issue in chapter 8.
Whomever Homo floresiensis was descended from, one thing is for sure.
LB1's virtual endocast revealed a highly convoluted cerebral cortex that
had a combination of features never before seen in a primate endocast
or brain. Some of these traits were advanced, and overall the endo-
cast appeared, at least to Scooter, Kirk, Fred, and me, to represent a
clear example of global neurological reorganization. Further, there was