Humidity Requirements of the Argentine Black and White Tegu
The Argentine Black and White Tegu, Tupinambis merianae, is found in the South American
countries of Brazil, Argentina, Paraguay, Uruguay, and Bolivia, south of the Amazon River12. In 2012 the
taxonomy of Argentine Black and White tegus was changed from Tupinambis merianae to Salvator
merianae. However, it was changed back to Tupinambis in 20133. Taxonomy and phylogeny data is not
widely agreed upon in the scientific community. For the purposes of this paper, the Argentine Black and
White Tegu will be referred to as T. merianae.
There are some basic data available on the web pertaining to the natural environment of the
Argentine tegu. In a study published in Herpetological Journal in 1994, some general observations of the
studied tegus’ habitat near an ecological reserve in Formosa, Argentina were noted. (This study was
published before a major taxonomical revision, so the researchers refer to the Argentine Black and
White tegu as Tupinambis teguixin4). Some of the observations were:
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the habitats were mostly flooded savannas and forests
the soil was made mostly of volcanic ash with poor drainage
the average ambient temperature was approximately 72F
the annual rainfall was about 48-75 inches (1200-1900mm)
some tegus had entered shallow water to eat prey such as snails, crabs, and fish5.
A scientific survey conducted in Minas Gerais in southeastern Brazil noted basic observations of
T. merianae as well. The researchers stated that tegus occupy a variety of environments including
clearings inside forests and forest edges; more specifically they found that many tegus spend their time
foraging on the edges of secondary forest and in old abandoned pastures. The researchers also found
wild Argentine tegus in urban areas in vacant lots and near small patches of forest6.
Other articles focus mainly on water use of reptiles; in one study, researchers observed tegus
during the “wet” and “dry” seasons in a national park in Brazil. One particular study by these researchers
aimed to find the average distance that tegus occurred from the nearest water source. The researchers
recorded positions of tegu sightings without disturbing the tegus. The study found that, throughout both
1
The Reptile Database: “Salvator Merianae”
Amphibia-Reptilia. Diet of juvenile tegu lizard Tupinambis merianae (Teiidae) in southeastern Brazil
3
Zootaxa. Review of Teiid Morphology with a Revised Taxonomy and Phylogeny of the Teiidae (Lepidosauria:
Squamata); Checklist of lizards and amphisbaenians of Argentina: an update
4
In 1995, taxonomical data was changed for some species of Teiids such as the Argentine tegu and the Columbian
tegu. The Argentine was formerly known as T. teguixin, but was changed to T. merianae. The Columbian was
known as T. nigropunctatus, and is known as T. teguixin today.
5
Herpetological Journal. The Diet of Adult Tupinambis Teguixin (Sauria: Teiidae) in the Eastern Chaco of Argentina
6
Check List. Lizards and Amphisbaenians, municipality of Vicosa, state of Minas Gerais, southeastern Brazil
2
seasons, over 50% of the tegu sightings were within 1000m of the nearest water source. In the dry
season particularly, over 70% of tegu sightings were within 500m of the nearest water source7.
The humidity of burrows constructed by terrestrial vertebrates in South America can be
predicted by certain characteristics of the climate and other conditions. In Santa Cruz de la Sierra,
Bolivia, an area that is within the range of the Argentine tegu, the average precipitation amount, the
average chance of precipitation, and the average relative humidity over 12 months are displayed in the
charts below8 9.
7
ProQuest Dissertations and Theses. Vertebrate ecology in caatinga: A. Distribution of wildlife in relation to water.
B. Diet of pumas (P. concolor) and relative abundance of fields
8
Information and graph(s) taken from Weatherspark.com
9
Information and graph(s) taken from Worldweatheronline.com
Argentine tegus get their common name because they are also found in northern Argentina. The
average precipitation, rainfall, and humidity for Formosa, Argentina are shown in the graphs below.
The Argentine tegu’s range also includes parts of Brazil. The data for average precipitation,
rainfall, and humidity for Belo Horizonte, Brazil is show below.
The countries of Paraguay and Uruguay are also home to the Argentine tegu. The corresponding
graphs for average precipitation, rainfall, and humidity are displayed below for Asuncion, Paraguay and
Montevideo, Uruguay.
The Argentine tegu is known to create and inhabit burrows in the wild, but not much is known in
the scientific community about the exact conditions of those burrows. There are not many public, peerreviewed journal articles to date that concern the humidity of the subterranean burrows of South
American vertebrates. However, one article describes burrow use in Chelonoidis carbonaria, the redfooted tortoise, in Bolivia10. A second article states that there are 11 species of armadillo throughout
South America that create large burrows that are utilized by other animals, such as tortoises11. It is
possible that Argentine tegus utilize these pre-constructed burrows, but humidity of these burrows has
remained unstudied.
T. merianae is becoming more common as a pet each day, and consequently more information
is being discovered pertaining to captive care that most resembles and imitates the natural
environment. Tegu owners are always sharing their care information online in herpetological forums,
such as “TeguTalk”. According to some of these forums, the majority of tegu keepers (not breeders) do
provide their tegus with artificial burrows (called “hides”), but not many of them monitor the moisture
conditions within the hide. Instead, tegu owners choose to keep the entire enclosure within a certain
humidity range. This range was determined by countless tegu owners who have experimented with
different moisture levels to find which was most ideal for the tegu. The range that nearly every tegu
owner suggests and uses is 60%-80% ambient humidity.
Tegu owners also share with each other the importance of moisture in the substrate. Most
owners say that the substrate in the enclosure should be the main source of humidity in the air.
Substrates that all tegu keepers recommend include moisture-retaining products such as organic top
soil, cypress mulch, play sand, orchid bark, and peat sphagnum moss. These substrates are also
recommended for their ability to retain a structure such as a burrow, if a tegu chooses to dig one.
Therefore, if the moisture in the substrate is keeping the humidity of the whole enclosure in the 60%80% range, it should be safe to assume that the moisture in a burrow would also be in this range or
higher. Tegu keepers generally do not monitor the exact moisture of the substrate, so there has not
been a general consensus among tegu owners on those specifications.
In conclusion, the Argentine Black and White Tegu is a species of lizard that comes from a more
humid environment, and in a captive environment they seem to be healthiest in a high-humidity
enclosure. Humidity in a captive environment should replicate that of the natural environment as closely
as possible in order to ensure the good health of the captive tegu.
Note: Because of the taxonomical revision in 1995, some research conducted in 1995 and the following
years may be inaccurate due to a mix-up of taxonomy, and research previous to 1995 may not be
available when searching for the correct species of tegu.
10
South American Journal of Herpetology. Activity Patterns and Burrow use in the Bolivian Chaco.
11
Journal of Mammalogy. Characteristics and use of burrows by four species of armadillos in Brazil.
Bibliography
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http://www.mapress.com/zootaxa/2012/f/z03459p156f.pdf
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