Lake Atitlán with its surface of 130 sq. km is the third largest freshwater lake in Guatemala. It is situated in the district of Sololá in the western highlands of Guatemala. The lake is approx. 18 km wide and 10 km long and lies at an altitude of 1,562 m. It is surrounded by three volcanoes: Atitlán (3,537 m), Tolimán (3,158 m) and San Pedro (2,995 m), which compose an imposing panorama around the highland lake.
Lake Atitlán lies in a crater, created by a great eruption of a volcano, the Chocoyos Eruption, approx. 85,000 years ago. As there is no outlet, the water level rose over the past years through the inlets of the principal rivers of the basin. The deepest point detected is approximately 340 m. The area is protected as Reserve of Multiple Uses of Basin Lake Atitlán – RUMCLA.
The natural vegetation of the region consists of broad leaved forests (cloudy and rainy), mixed pine-oak and conifer forests. Xeric Association can be found in the shore region of the lake, with characteristic animals and vegetation.
Furthermore, 798 different plant species occur in the region, 61 of them are endemic. The rich biodiversity includes also animal species: 116 species of reptiles and amphibians, 12 species of them are endemic, such as the Salamander species Bolitoglossa franklini, B. flaviventris, B. flavimembris, B. engelhardtii and Oedipina stenopodia. and other species such as Arboreal Alligator Lizard (Abronia matudai) or Botriechis bicolor. In the RUMCLA live 30 % of lizards, 40 % of snakes, 36 % of amphibians registered in Guatemala .
236 bird species are found there, 28 % of them are listed in the Red List of Threatened Species (67 in total), and 12 species are endemic or from restricted areas: Pink-headed Warbler (Ergaticus versicolor), Brown-backed Solitaire (Myadestes occidentalis), the national bird of Guatemala Resplendent Quetzal (Pharomachrus mocinno), Blue-throated Toucanet (Aulacorhynchus prasinus), Atitlan Grebe (Podylimbus gigas), Azure-rumped Tanager (Tangara cabanisi) and Horned Guan (Oreophasis derbianus). Many migratory birds use Lake Atitlán as a wintering ground: Pied-billed Grebe (Podylimbus podiceps), Ruddy Duck (Oxyura jamaicensis) and American Coot (Fulica Americana). Roadrunners (Geococcyx velox), which are typical for Xeric Associations occur in the region as well.
The unique biodiversity is also reflected in the occurrence of mammals. From the 141 species found there, 7 are endemic: Guatemalan Deer Mouse (Peromyscus guatemalensis), Black-handed Spider Monkey (Ateles geoffroyi) and Northern Tamandua (Tamandua mexicana). Many of the species mentioned before are listed in the Red Data Book, and 28 % of the total species of mammals (39 species) living in RUMCLA arelisted in the Red List of Species of the National Council of Protected Areas in Guatemala (CONAP).
Today three Mayan groups still live at Lake Atitlán: the K´iche´e live in the higher regions, the Kaqchikel in the North and the East, the Tz´utujil in the South. The old traditions have been preserved until today and exist in a religious syncretism with the Christian rituals established during the Spanish colonial time.
In spite of the rich biodiversity, landscape and culture,it is one of Guatenmala’s poorest regions. The population depends on subsistence cropping, added by income from tourism, because Lake Atitlán is the second most visited tourist place in Guatemala. Handicraft is the most important commercial activity, also pottery and paintings are made and sold.