My iguana sleeps in the sun alll day?

i just got to iguanas and they are about 6 inches long (not including tale) they lay in the sun all day and don't ever go to the shade. The temp is about 85-90 deg. and the other is about 75- 80 deg. every now and then one will go swimming... (extravagant tank, about 130 gallons). Do they just love the sun that much or what? also is it ok to get one out and hold it.... ( they also have brite green bodies and one has a half blue head)