Digestive tracts differ for different animals. - In comparisons, consider lifestyles and evolutionary history of animals. Pancreas marks duodenum. Jejunum, ileum: attaches to large intestine and colon ...

They are then swallowed and mature into adult worms in the small bowel, particularly the jejunum. Adult hookworms are 5 mm to 13 mm in length and produce between 5000 and 25 000 eggs per day.