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Gila Monster
Heloderma suspectum
Silhouette: Nicolas Mongiardino Koch · PhyloPic
- KingdomAnimalia (Animals)
- PhylumChordata (Chordates)
- ClassSquamata
- FamilyHelodermatidae (Beaded Lizards)
- GenusHeloderma (Beaded Lizards)
- SpeciesHeloderma suspectum (Gila Monster)
In 3 days ~50% in a week ~80%
619 Verified sightings at Saguaro National Park From 2019 to 2026
619 In 1 park
April Best month
☀️🌙 Day & Night When it's spotted
About the Gila Monster
The Gila monster ( HEE-lə; Heloderma suspectum) is a species of venomous lizard native to the Southwestern United States and the northwestern Mexican state of Sonora. It is a heavy, slow-moving reptile, up to 22 in (56 cm) long, and it is the only venomous lizard native to the United States. The Gila monster is sluggish in nature, so it is not generally dangerous and very rarely poses a real threat to humans, though the bite is painful. Nonetheless, it has a fearsome reputation and is sometimes killed despite the species being protected by state law in Arizona.
The lower teeth have venom grooves to transmit the venom to the prey. The venom contains multiple peptides; one of these, exendin-4, formed the basis for the development of the GLP-1 receptor agonists, used to treat type 2 diabetes and obesity.
The name "Gila" refers to the Gila River Basin in the U.S. states of Arizona and New Mexico, where the Gila monster was once plentiful. Heloderma means "studded skin", from the Ancient Greek words helos (ἧλος), "the head of a nail or stud", and derma (δέρμα), "skin". The species epithet suspectum comes from the describer, paleontologist Edward Drinker Cope. At first, this... Wikipedia →
Recent sightings of Gila Monster in Saguaro National Park
LIVEiNaturalistGlobal Distribution
Parks Where Found
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Saguaro National Park | 🇺🇸 United States |
More parks will be added in future updates.
Zoos & Centres Where Found
Closest Relatives at Saguaro National Park
No species of the same family or order lives in Saguaro National Park, so these are its closest relatives here: other reptiles.
Before you go
What are the chances of seeing a Gila Monster in Saguaro National Park?
Possible
About 20% of wildlife watchers report a Gila Monster sighting in Saguaro National Park on a given day, based on 619 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 16th most-seen of the 51 reptiles we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
When is the best time to see a Gila Monster in Saguaro National Park?
April to June
In those months about 30% of wildlife watchers report a Gila Monster in Saguaro National Park on a given day, against under 5% in January and February, the lowest months. Those are among Saguaro National Park's driest months, with about 5 mm of rain a month against 55 mm in July.
What time of day is best to see a Gila Monster?
Between 7 and 10 pm
Across all the parks we cover, that three-hour window holds the most Gila Monster sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.
Where else can you see a Gila Monster?
Only Saguaro National Park, in our data
Saguaro National Park is the only park on Wallace's Line with enough records to rate Gila Monster sightings: about 20% of wildlife watchers there report one on a given day.
Where does the Gila Monster sighting chance come from?
GBIF citizen-science records
It is estimated from how often the Gila Monster is recorded against all the reptiles logged in Saguaro National Park (619 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
