The animals that are gyrencephalic are primates, cetaceans and marine mammals, ungulates (hoofed mammals), carnivorans, proboscideans and marsupials.
These animals that are gyrencephalic include.
Primates: Humans, chimpanzees, gorillas, and most monkeys.
Cetaceans & Marine Mammals: Dolphins, orcas, and whales.
Ungulates (hoofed mammals): Pigs, cows, sheep, horses, and hippopotamuses.
Carnivorans: Dogs, cats, lions, and ferrets.
Proboscideans: African and Asian elephants.
Marsupials: Kangaroos and wombats.
Gyrencephalic animals are animals that have deeply folded cerebral cortices, which feature raised ridges, (gyri) and sunken grooves (sulci).
The folding allows mammals to pack larger and more complex brain surfaces in their skulls.
And in contrast, small mammals like rats, mice and manatees, often have smooth brains and are instead known as lissencephalic.
Lissencephalic refers to a brain that has a smooth surface, lacking the normal folds (gyri) and grooves (sulci) found in most humans and advanced mammals.
Depending on the context, this term can refer to a rare human medical condition or a normal trait in certain species.
In humans, a lissencephalic brain is a rare, severe neurological disorder literally translating to "smooth brain".
The smooth brain in humans occurs due to defective cell migration during the 12th to 24th weeks of embryonic development.
It leads to severe intellectual disability, developmental delays, intractable epilepsy (seizures), and poor muscle tone.
Life expectancy is typically shortened, and individuals often require 24/7 supportive care.
Some mammals (such as mice, rats, and manatees) naturally have lissencephalic brains.
Unlike in humans, a smooth cortex is completely normal for these animals.
Their brains are small enough that the cells are still fully functional without the need for increased surface area provided by folds.