jaguar
jellyfish
jaybird
jerboa
jackal
jackrabbit
kangaroo
urubu
a yak
Quail
my favorite thing to do that start with a j is to go on journey which means travel around the world.
Koala
A Venus flytrap.
There is New Jersey but that is the closest thing to a state starting with the letter "J".
Quartz
Quail
jump rope, Jack Russell Terrier
Juicer, or Julliene Fry maker