OHMEGA/MONSTER

2026 study provides new evidence that very young T. rex hatchlings fed early, but not hunting from birth

The *Biology* paper’s fossil identification and bone structure support hatchlings that likely fed at an early stage, while tooth-wear evidence still leaves independent hunting from birth unproven and compatible with scavenging.

Canada

A new Biology study makes the baby Tyrannosaurus rex case much more concrete than it was before. Figure 1 labels RSKM P2416.82 as T. rex left metatarsal III from the latest Maastrichtian Frenchman Formation of Saskatchewan, and Figure 2 reconstructs a perinate T. rex from that bone, scaled to 84% of its linear dimensions.

Where the baby T. rex foot bone came from (Frenchman Formation, Saskatchewan)

This map orients a reader to the Canadian location and the stratigraphic setting tied to the juvenile T. rex specimen (RSKM P2416.82), making clear where the evidence fits in geography. This map places the juvenile T. rex foot bone RSKM P2416.82 (left metatarsal III) in the latest Maastrichtian Frenchman Formation of southwestern Saskatchewan, Canada, with Eastend and Regina as reference cities. The amber point for the formation uses Wikipedia’s published type-area coordinates along the Frenchman River (49.49073°N, 108.90467°W); the scientific paper and news coverage locate the specimen only at formation/province level, so this is not a precise quarry pin. Sources: Wikipedia Frenchman Formation, Eastend, Regina; specimen context from Longrich et al., Biology (2026) / Royal Saskatchewan Museum collections reporting. Basemap: Natural Earth 110m admin-0 countries. As of 2026-07-25. — AI-assisted analytic, built only from real cited or sourced data. Source: FOX Weather, Discover Magazine. As of 2026-07-25.

The paper then backs that identification with bone-structure evidence. Figure 8 shows synchrotron computed microtomography of the metatarsal with extensive vascularization, longitudinal canals, and well-developed cancellous structure; Figure 9 shows serial sagittal sections described as highly vascularized bone characteristic of very young, rapidly growing dinosaurs; and Figure 11 describes a transition between embryonic and hatchling bone, while using cautious language such as “possibly” and “likely” for the hatching-line interpretation. A hatching line is the bone boundary that marks the shift from embryo to hatchling, and precociality means young animals could function on their own relatively early instead of staying helpless in the nest for long.

The study is broader than one fossil. Its figure set includes clutch/litter-size and growth-curve analyses across tyrannosaurs and other amniotes, and the abstract says hatchlings of T. rex and Gorgosaurus libratus were under a year old, weighed about 2.5 kg and 2.4 kg, and had teeth showing wear suggesting they fed on relatively large vertebrates. Tooth wear here means abrasion patterns on the teeth themselves; in this debate, worn teeth are taken as evidence of feeding, but not automatically of killing.

That feeding evidence is real, but it is still not the same thing as proof of independent hunting from birth. The paper’s own abstract says the hatchlings’ small size and precociality suggest limited parental care; secondary coverage describes the predation claim as an inference from worn teeth and comparisons with living animals; and older tyrannosaur literature shows tooth marks and feeding traces can record scavenging or postmortem carcass use as well as predation.

The distinction is simple. Tooth wear shows feeding, but the paper treats the hunting-from-birth part as inference because worn teeth can also fit carcass feeding. The evidence visible here supports a stronger claim than many readers would have assumed: hatchling tyrannosaurs were real, very young animals, and they probably fed early. What remains open is the larger behavioral leap to routine, independent hunting from birth. The accessible record does not close that gap, and it does not rule out scavenging or other carcass-feeding explanations.

That caution matters because tyrannosaur feeding has long been treated as mixed ecology rather than a clean predator-versus-scavenger binary. Thomas Holtz’s 2008 reappraisal argued that tyrannosaurs were not obligate scavengers, and that leaves room for a spectrum of feeding behaviors rather than a single fixed mode. On that background, the hatchling tooth wear is suggestive evidence for early feeding, not a standalone smoking gun for hunting from day one.

The reproductive-strategy angle is also part of the paper, but it should stay in its lane. The abstract estimates roughly 20 eggs for a small adult T. rex and about 30 for the largest adults, and the study’s figure set includes clutch/litter-size and growth-curve analyses. Secondary coverage then extends that into a “light touch” parenting picture. That is a plausible downstream inference, but not something the visible figure-level evidence alone fully settles.

So the clean read is narrower than the loudest headline. The 2026 Biology paper materially strengthens the case that very young T. rex existed as identifiable hatchlings and that they fed early. What remains unresolved is whether that early feeding amounted to independent hunting from birth. In the evidence visible here, that stronger claim is still inference, not closure.

Source recordSources / claims / limits

How this piece is framed: A verification-led frame: the center of mass is the evidentiary boundary inside the 2026 Biology study — what the paper’s snapshotted figures directly support (specimen identity, imaging/histology of a very young animal, and tooth-wear evidence consistent with feeding) versus what still depends on secondary summaries or unverified text (sample size, full methods, formal limitations, and the leap from early feeding to hunting from birth).

Charts & tables — each built only from the cited claims below, by an AI tool

  • Where the baby T. rex foot bone came from (Frenchman Formation, Saskatchewan) — from claims clm_7c8c36248e, clm_b1fe83468f · as of 2026-07-25 · ⚠ figures not all matched to the cited claims: 2416.82, 49.49073, 108.90467, 49.5139, 108.8195, 50.45472, 104.60667

Sources

Claims, and how far we tracked each down

  • [confirmed] Figure 1 of the Biology paper explicitly labels RSKM P2416.82 as T. rex, left metatarsal III, from the latest Maastrichtian Frenchman Formation of Saskatchewan, and shows anterior, posterior, medial, lateral, distal, and proximal views. · read in full (as of 2026-07-25)
  • [confirmed] Figure 2 reconstructs a perinate T. rex from the third metatarsal RSKM P2416.82 and states that the post-hatching individual was scaled to 84% of the linear dimensions of that bone. · read in full (as of 2026-07-25)
  • [confirmed] Figure 8 describes synchrotron computed microtomography of RSKM P2416.82 and identifies extensive vascularization, longitudinal canals, and well-developed cancellous structure. · read in full (as of 2026-07-25)
  • [confirmed] Figure 9 states that serial sagittal sections of RSKM P2416.82 show highly vascularized bone characteristic of very young, rapidly growing dinosaurs. · read in full (as of 2026-07-25)
  • [confirmed] Figure 11 interprets RSKM P2416.82 as showing a transition between embryonic and hatchling bone, while using cautious language such as possibly representing a hatching line and likely transition. · read in full (as of 2026-07-25)
  • [confirmed] The paper’s figure set includes clutch/litter size and growth-curve analyses for tyrannosaurs and other amniotes, indicating that reproductive-strategy inference is an explicit analytic component of the study rather than only a news-summary extrapolation. · read in full (as of 2026-07-25)
  • [confirmed] The article metadata shows the paper was submitted on 13 April 2026, revised on 13 June 2026, accepted on 19 June 2026, and published on 7 July 2026. · read in full (as of 2026-07-25)
  • [confirmed] The paper’s abstract says hatchling teeth show wear suggesting they fed on relatively large vertebrates. · read in full (as of 2026-07-25)
  • [likely] The accessible coverage of the 2026 Biology study supports early feeding and precociality in hatchling tyrannosaurs, but does not by itself prove routine independent hunting from birth. · read in full (as of 2026-07-25)
  • [likely] The ScienceAlert coverage explicitly phrases hatchling predation as an inference from worn teeth and comparisons to living animals, not as direct behavioral observation. · read in full (as of 2026-07-25)
  • [confirmed] Hone and Watabe showed that tyrannosaurid tooth marks on bones can record scavenging or postmortem carcass processing, so tooth traces alone do not prove a kill. · read in full (as of 2026-07-25)
  • [confirmed] Therrien et al. explicitly note that bite marks and feeding traces are difficult to distinguish from scavenging, and that juvenile tyrannosaur bite traces may reflect later-stage carcass consumption rather than live hunting. · read in full (as of 2026-07-25)
  • [likely] Thomas R. Holtz Jr. argued in a reappraisal of the scavenging hypothesis that tyrannosaur anatomy does not justify treating T. rex as an obligate scavenger. · read in full (as of 2026-07-25)
  • [confirmed] The paper’s abstract estimates about 20 eggs for a small adult T. rex, about 30 for the largest T. rex, and says larger clutches of 50 or even 100 eggs are not impossible. · read in full (as of 2026-07-25)
  • [likely] The paper estimates a small adult T. rex may have laid about 20 eggs and a larger adult about 30 eggs. · read in full (as of 2026-07-25)
  • [likely] The authors suggest T. rex parenting involved relatively low direct investment, with hatchlings leaving the nest early. · read in full (as of 2026-07-25)
  • [likely] The authors interpret the fossils to mean that T. rex hatchlings were active predators shortly after birth. · read in full (as of 2026-07-25)

Where we hit a limit / what to double-check