Both the black rhinoceros and the white rhinoceros are critically endangered species. Their numbers are shrinking, with fewer than 20,000 to be found in the wild. Using a rhinoceros to symbolize an expanding Federal deficit would just seem to be lazy cartooning. But then again, the Creepy Chicago Tribune Cartoonist™.
A better symbol would be Donald J Trump -- the largest Ex-President since William Howard Taft. Trump weighs in at a whopping 322 pounds, which has been steadily increasing since his inauguration in 2017:
Just Sayin!