Prehistoric effigy mounds are known almost exclusively on the North American continent, primarily in the north-central United States. They are also found in northern Mexico at a single site, Paquime, and in a few isolated cases in the Andes. Our team of Peruvian and US archaeologists was therefore surprised to find numerous mounds, interpreted as animal effigy mounds, constructed in several Peruvian coastal valleys. While geoglyphs are common in Peruvian coastal valleys, they differ from effigy mounds in that they lack three-dimensional structure; both types of monuments are however similar in that they are best viewed from overhead. Excluded from this discussion, because they are more recent, are two Peruvian Inca sites at Cuzco and Ollataytambo.
Our survey found Preceramic animal effigy mounds ranging from 5m to 400m in length. One set of 31 mostly smaller mounds lies in the valley floor to the west of the Late Preceramic site of Buena Vista in the Chillón Valley. In the Chillón Valley too are four mounds, two giant and two smaller, associated with the Late Preceramic site of El Paraíso 35km down the valley from Buena Vista. Another set, only some of which we have mapped, exist in the Casma Valley. Presented here are four giant mounds (two pairs) — one from the Chillón Valley and one from the middle Casma Valley (Figure 1) — that have been surveyed on the ground. Each is more than 200m in length and can be associated with adjacent Late Preceramic sites dating from 1750 to 2200 BC (Benfer & Adkins 2010).
The Chillón Valley
The Chillón Valley site described here lies less than 2.5km from the coast and is surrounded by irrigated fields. Figure 2 shows these mounds at the site of El Paraíso (Engel 1966): the upper mound (A) resembles an Andean condor with an 'eye' made of intensely burned earth and ash, while the lower figure (B) can be interpreted as a crouching animal figure. Both are oriented towards the seasonal or nightly extreme described by the Milky Way, which Quilter (1991) had noted as the general orientation of the site. Figure 3 shows two figures, 'monsters' incised into bone, found at late Preceramic sites in the Casma Valley (Bischof 1994: 224, fig. 27b & e) the upper has the canine pattern of a cayman, the lower that of a puma, while the paws may be those of another animal (a common pattern in later Andean art was to depict body parts of different animals; see Rowe 1962). Bearing in mind differences in scale, the lower mound in Figure 2 (B) bears resemblance with these animal images. The triple point motif at the head and circles also resembles serpent figures from the same time period (Suárez Ubillus 2010: fig. 17a–c). Figure 4 is a profile of the mound shown in Figure 2(B): it is not a flat platform but instead has sharply defined surface contours. It is constructed of rocks on top of what appears to be a prepared earthen platform, but geomorphological investigation is necessary to rule out deflation of surrounding fields as the cause for this 1–2m elevation of the mound. It should be noted that round and rectangular stone structures are found within this and other giant effigy mounds.
The Casma Valley
Figure 5 shows our map and a Google Earth image of one of the more impressive effigy mounds, El Olivár Bajo, found in the middle Casma Valley at 350m asl on the northern Peruvian coast. This site, which dates to the Preceramic period, may represent a bird; a large bird geoglyph is also known from the valley (Pozorski et al. 1991). The mound has a central platform with flanking monoliths (Figure 6). Just to the north and east of this figure is another mound (Figure 7, top right: sinuous shape marked at the 'head' by arrow and 64°) which could be interpreted as bird-shaped too. It is notable that both Casma figures are 'looking' towards an azimuth of 64° (Figure 7), which is the azimuth of the June solstice sunrise. The actual sunrise in 2000 BC over a ridge with an altitude of approximately 9° would have been observed at 63°4' (Starry Night Pro V. 5). In a recent survey of the orientation of monumental constructions in the Casma Valley, we found indeed that they followed astronomical orientations that are more modal than chance would have predicted (Benfer & Adkins 2010).
Peru is famous for its geoglyphs but animal effigy mounds have not been reported in the Andes previously except for isolated cases (e.g. llamas in the Santa Valley; Wilson 1998). The mythical condor is well known over much of South America (Urton 1981; Arnold & Espejo Ayca 2006), condor images of rocks are common in the Andes (Sánchez Garrafa 1999) and condors have also been depicted in petroglyphs, for example in a petroglyph at Calyipuy dated to 1000 BC (Bueno Mendoza 2006). At Buena Vista, accepting that the carved stone pillar, one of a pair on a ridge, is a condor, this important symbol marks the equinoctial sunrise from a temple which hosts a number of astronomical viewing points (Benfer in press 2011; Benfer & Adkins 2008; Benfer et al. 2010 & 2011). The lower effigy mound at El Paraíso may represent a cayman or puma, and the two mounds from the Casma valley are interpreted as birds. The simplest explanation for these mounds is that they represent animals that mirror those in the Andean Zodiac, in the same manner as North American effigy mounds may be seen as representing animals of their respective constellations (Bernardini 2004). More fieldwork and investigation of ethnographic and ethnohistoric sources will be necessary to test this interpretation.
The Curtiss and Mary G. Brennan Foundation supported this work. The Museum of Anthropology and Pre-Columbian Agriculture of the National Agricultural University of Peru provided laboratory and technical support. Henning Biscof provided valuable critique. Louanna Furbee and Monica Barnes provided useful criticisms. The field team of Bernardino Ojeda, Omar Ventocilla, Andrés Ocas, and Lucio Laura produced maps and valuable observations.
1 The citation was corrected on 19 December 2011.