Tim Higham

Tim Higham Appointed Director of the UCR Natural Reserves System

tomwt — Fri, 03 Apr 2026 17:30:53 +0000

Tim Higham Appointed Director of the UCR Natural Reserves System tomwt Fri, 04/03/2026 - 10:30 More College News April 03, 2026

Professor Tim Higham

I am very pleased to announce the appointment, after an internal search, of Professor Tim Higham as the new Director of the UCR Natural Reserves System. Professor Higham will succeed Professor Kimberly Hammond, who is stepping down from this position. Professor Higham joined the Department of Evolution, Ecology and Organismal Biology in 2011. Over the past 15 years, Professor Higham has conducted interdisciplinary research on the relationships between the environment and animal function, using a diverse array of measurements of both habitats and animal motion. His studies have included fish, lizards, snakes, small mamals and birds. Professor Higham has maintained a very strong field component to his research, with field sites in Namibia, South Africa, the West Indies, British Columbia, Baja California, and the Mojave Desert.

Professor Higham will commence his appointment on April 1, 2026. The College is sincerely grateful to Professor Hammond for providing overlap with Tim during the next three months and for her phenomenal and inspiring leadership of the UCR NRS over many years. Her contributions to the NRS will be the subject of a future email from me.

Please join with me in welcoming Professor Higham to this important leadership position in CNAS and within the entire UC Natural Reserve System.

Sincerely,
Peter

Peter W. Atkinson, Ph.D.
Dean - College of Natural & Agricultural Sciences

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UCR Natural Reserves

Tim Higham

Megalodon may have been ‘even longer’ than we thought

tomwt — Thu, 13 Mar 2025 14:55:21 +0000

Megalodon may have been ‘even longer’ than we thought tomwt Thu, 03/13/2025 - 07:55 More CNAS in the Media Andrew Paul | Popular Science March 09, 2025

POPULAR SCIENCE - If you picture a megalodon, chances are you envision what amounts to a gigantic great white shark. The image is understandable, given almost every depiction of the ancient apex predators across research and pop culture. But last year, an international team put forth a new anatomical design based on their analysis of incomplete fossilized vertebrae. According to the researchers, the famous megalodon was likely “more slender and possibly even longer” than the prevailing theory. Rather than a great white, the team offered sleeker mako sharks for a frame of reference.

The hypothesis kicked off a heated debate among paleobiologists, many of whom contended the evidence still simply didn’t support giant prehistoric makos. Unfortunately, a follow-up study likely won’t satisfy anyone who disagrees with the mako idea, either. According to many of the original study’s authors, megalodons may have been even longer and leaner than they first proposed. In terms of today’s shark parallels, think less “mako” and more “lemon.”

The revised shape and size is detailed in a paper published on March 9 in the journal Palaeontologia Electronica. After comparing portions of a megalodon’s vertebral column to over 100 species of living and extinct shark species, researchers now estimate the megalodon may have topped out at around 80-feet-long, or about two school buses, while weighing as much as 94 tons—roughly as massive as a blue whale. For reference, the predominant megalodon theory puts them at 50-65 feet long and 53-115 tons. Based on their conclusions, even newborn megalodons were sizable creatures, and likely measured as large as a modern adult great white.

“It is entirely possible that megalodon pups were already taking down marine mammals shortly after being born,” Phillip Sternes, a co-author on both papers, argued in an accompanying statement. Sternes also contends the latest study “provides the most robust analysis yet of megalodon’s body size and shape.”

“Rather than resembling an oversized great white shark, it was actually more like an enormous lemon shark, with a more slender, elongated body,” he said. “That shape makes a lot more sense for moving efficiently through water.”

While the great white shark’s bulkier, torpedo-like frame makes it perfect for quick bursts of speed, the lemon shark evolved for energy-efficient, sustained ocean cruising. This concept of evolutionary efficiency played into the team’s alternative theory, as well. Tim Higham, a study co-author and biologist at University of California Riverside, offered Olympic swimmers as a comparison.

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Department of Evolution, Ecology and Organismal Biology

Tim Higham

When the ocean got hot, the sharks bulked up

tomwt — Mon, 08 Jul 2024 20:38:30 +0000

When the ocean got hot, the sharks bulked up tomwt Mon, 07/08/2024 - 13:38 More CNAS in the Media Laura Baisas | Popular Science July 08, 2024

POPULAR SCIENCE - A giant spike in ocean temperatures about 93 million years ago may have helped sharks grow from stubby bottom dwellers into bigger predators. This surge in ocean heat in the Cretaceous period came from a gush of volcanic lava that sent carbon dioxide levels skyrocketing. This created a greenhouse effect that raised ocean temperatures. In response, some shark species evolved elongated pectoral fins that helped make them faster and move to a different part of the water column in order to eat. The findings are described in a study published last month in the journal Current Biology.

Earlier research published in 2018 found that a Cretaceous shark called Cretoxyrhina mantelli (pictured above) was large enough to eat a pterosaur. The fossil record not only contains evidence of how sharks interacted with other animals in their environment, but also what their teeth were like and how large they were. The team on the study published in 2024 took body length and fin measurements from over 500 fossilized and shark species to estimate how their pectoral fins have changed over time.

“The pectoral fins are a critical structure, comparable to our arms,” study co-author and University of California, Riverside (UCR) biology PhD student Phillip Sternes said in a statement. “What we saw upon review of a massive data set, was that these fins changed shape as sharks expanded their habitat from the bottom to the open ocean.”

The longer pectoral fins help make sharks movements more efficient. According to Sternes, their fins are long and narrow like the wings of an airplane to reduce the amount of energy needed for movement. The team also saw that the open-water sharks appear to have gotten faster, compared to the bottom dwellers.

“Shark muscle is very sensitive to temperature,” study co-author and UCR biologist Tim Higham said in a statement. “The data helped us make a correlation between higher temperatures, tail movement, and swimming speeds.”

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Department of Evolution, Ecology and Organismal Biology

Tim Higham

Fearsome sharks of today evolved when ancient oceans got hot

tomwt — Mon, 08 Jul 2024 20:25:52 +0000

Fearsome sharks of today evolved when ancient oceans got hot tomwt Mon, 07/08/2024 - 13:25 More CNAS in the Media Jeanne Timmons | The New York Times July 08, 2024

THE NEW YORK TIMES - It sounds like something out of a Hollywood film script, but it really happened: Shark-evolution researchers say that increased ocean temperatures more than 100 million years ago may have caused sharks to grow bigger, swim faster and become the powerful predators we know today.

In a paper published last month in the journal Current Biology, scientists reported that they measured fin sizes and body lengths of 500 extinct and living sharks and compared that information with data from the evolutionary shark family tree. Their results indicate that when the ocean got very hot approximately 122 million years ago during the Cretaceous period, some sharks abandoned their habitat on the seafloor and moved up into the open ocean. That ascent may have altered their fin and body structure, which led to changes in their size and ability to swim.

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Sharks and other fish are similar to most animals, Timothy Higham, a co-author and professor at the University of California, Riverside, explained, “in that the muscle function is very temperature-dependent.” In other words, he said, “if your muscles warm up, they become better at contracting quickly.”

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Department of Evolution, Ecology and Organismal Biology

Tim Higham