As in Mexico, climate corresponds with the degree of elevation, and in Guatemala the same three zones, _tierra caliente_, _tierra templada_ and _tierra fria_, are found, with similar abrupt transitions from one to the other. In the lower country cacao, vanilla, rubber, coconuts, bananas and palms grow freely, while the uplands are covered with oak and pine. The Atlantic side of Honduras produces a variety of valuable tropical timber, while the higher ground is on the whole more open than that of Guatemala, much of the vegetation being herbaceous and affording good grazing. The climate of Yucatan is purely tropical, and the rainfall is very heavy. Under such conditions, more favourable to vegetable than human existence, the country is thickly covered with forest which reappears as soon as cleared and renders exploration a matter of great difficulty, besides making the country very unhealthy from the point of view of the European. Indeed, the thick vegetation which clothes the river valleys and lower lying parts of the whole Maya area is the principal obstacle in the way of archæological investigation, since not only does it render the ruins extremely difficult to locate, but it also contributes very seriously to their decay. The fauna is rich, and includes birds of brilliant plumage in great variety, jaguar, peccary, deer and alligator; the deer and the turkey being the most important from the economic point of view of the early native. [Illustration: FIG. 45. 1. Aztec. 2. Pipil. 3. Chontal. 4. Zotzil. 5. Tzental. 6. Chol. 7. Chanabal. 8. Chicomaceltec. 10. Cuje. 11. Jacaltec. 12. Mam. 13. Ixil. 14. Aguacatec. 15. Quiché. 16. Kakchiquel. 17. Tzutuhil. 18. Uspantec. 19. Kekchi. 20. Pokonchi. 21. Pokomam. 22. Chorti. 23. Maya. 24. Zoque. 25. Tapachula. (1 and 2, Nahuatl; 3–23, Maya; 24 and 25, Zoquean.)]