A common question is which dinosaur possessed the most teeth, often leading to the exaggerated claim of having a million. This fascination stems from the remarkable specializations that certain herbivores developed to process tough plant material. While no dinosaur ever held a million teeth at one time, the true number and the mechanics behind it are arguably more astonishing than the sensationalized figure.
The Dinosaur with the Dental Battery
The dinosaur at the center of this dental mystery is Nigersaurus taqueti, a species that lived in the middle Cretaceous period, around 115 to 105 million years ago. This ancient creature belonged to the Rebbachisauridae family, a group of sauropods. Fossils of Nigersaurus were discovered in the Elrhaz Formation in the Republic of Niger in West Africa, which is the source of its name.
Measuring about 30 feet in length and weighing around two to four tons, Nigersaurus was relatively small for a sauropod, but its skull contained its most unique feature. Paleontologist Paul Sereno nicknamed it the “Mesozoic vacuum cleaner” because of its wide, flat jaw structure. This bizarre jaw was a highly specialized feeding tool, designed not for crushing, but for efficiently harvesting low-lying vegetation.
Anatomy of the Super-Toothed Jaw
The unusual appearance of Nigersaurus is due to its highly specialized dental arrangement, known as a dental battery. In this setup, the teeth are organized into vertical columns embedded deep within the jawbone. Each column contains one functional tooth at the surface and a stack of up to nine replacement teeth waiting beneath it.
The total number of teeth present in the mouth at any given moment, including both active and replacement teeth, was approximately 500 to 600. These teeth were grouped together at the very front of the square-shaped muzzle. The tooth-bearing bones were rotated, positioning all the teeth far forward, perpendicular to the long axis of the skull. This configuration made the mouth resemble a wide, straight shear or a pair of hedge clippers. The enamel on the teeth was highly asymmetrical, being up to ten times thicker on the outer, exposed side to resist the constant abrasion from its diet.
Unpacking the “Million Teeth” Myth
That massive number does not represent the teeth Nigersaurus held at one time, but the estimated total number of teeth it produced over its entire lifespan. This lifetime production total is driven by the dinosaur’s astonishingly fast tooth replacement rate, the quickest known for any dinosaur.
The wear from its abrasive, ground-level diet meant that each individual tooth was worn down and replaced with a new one from the dental battery at a rapid pace. Scientific analysis of the growth lines within the tooth structure revealed that Nigersaurus replaced every single tooth in its mouth approximately once every 14 days.
When this rapid replacement cycle is calculated over a projected multi-decade lifespan, the cumulative number of teeth produced by the columns in the dental battery reaches a tremendous total. It is this lifetime count of hundreds of thousands of teeth that eventually gets exaggerated into the legendary “million teeth” figure.
Lifestyle and Feeding Mechanics
Nigersaurus was a low-level grazer, meaning it fed exclusively on vegetation found close to the ground, likely sweeping its head side-to-side like a lawnmower. Its diet consisted of tough, abrasive plants such as ferns, horsetails, and early flowering plants, as grass had not yet evolved.
The wide, square muzzle and the position of its teeth allowed the dinosaur to crop large amounts of this low-lying foliage in a single sweep. The constant, rapid replacement of teeth ensured that the cropping edges remained sharp despite the grit and silica content of the plants it consumed. This unique feeding strategy allowed Nigersaurus to occupy an ecological role similar to a modern cow. Its short neck and the orientation of its inner ear canals suggest its head was habitually held downward, perfectly positioned for nonstop grazing near the surface.