An Ultimate Guide to the Baculites: Staff-Like

Leave a comment / / Updated on: 24th September 2023

Name Meaning“Staff-like or walking stick rock”Height5-20 mm whorl height
PronunciationBAH-ku-laitsLength7-200 cm (0.23-6.6 ft)
EraMesozoicLate CretaceousWeight0.15-2.5 lbs (68 – 1604 grams)
ClassificationCephalopoda, Ammonitida, BaculitidaeLocationNorth America and Europe

Baculites Pictures

Baculites | Vac1 via iStock

The Baculites

Gage Beasley Prehistoric's Baculites Concept
Gage Beasley Prehistoric’s Baculites Concept

Baculites is a funny-looking creature that may not look like an animal at first glance.

Still, this is one extinct genus of heteromorph ammonite cephalopods widely distributed throughout most of the Late Cretaceous period of the Mesozoic Era (over 65 million years ago).

In fact, this creature briefly outlived the K-Pg mass extinction event, which wiped out about three-quarters of the animal and plant species on Earth and marked the end of the Cretaceous period, and by extension, the Mesozoic Era. 

Baculites was named in 1799 by Lamarck, and it’s also called walking stick rock because of its almost straight shells.

There is only limited information about Baculites, which is enough to gain some insight into the life of these ammonite cephalopods. 

Read on to find out more about this intriguing creature.

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

Baculites have almost straight shells, and generally, these shells slant dorso-ventrally forward and may be smooth or striated. In the same way, the aperture slopes toward the front and has a curved margin. 

Dorsum is broader than the venter, which is rounded to acute. 

Gage Beasley Prehistoric's Baculites Size Comparison Chart
Gage Beasley Prehistoric’s Baculites Size Comparison Chart

The juvenile shell is coiled in a couple of whorls at the apex and is approximately 0.39 inches in diameter. 

A Baculite adult can grow between 2.8 inches and 6.6 feet long.

The diagonal ribbing or striations found on Baculites make scientists believe it had a horizontal orientation in its adult years. 

This feature is similar to marine cephalopods, such as Clitendoceras and Bassleroceras, that lived in the Ordovician Period. 

However, another group of researchers believes that Baculites had a vertical orientation instead because its head hung vertically without an apical counterweight, restricting its movement in that direction. 

More recent research has shown that these animals were, in fact, horizontally oriented creatures.

Like other ammonites, Baculites’ shell comprises several chambers linked to the creature by a narrow tube (siphuncle). 

Holotype of Baculites ovatus
Holotype of Baculites ovatus | Matthewhalley via Wikipedia CC BY-SA 4.0

This siphuncle regulates gas content, which also helps with the animal’s buoyancy. 

While these chambers are linked with the siphuncle, they are also separated by walls called septa. 

Each septum meets the outer shell through a line called a suture. 

And like every other ammonite, their shells feature unique suture patterns that can be used to recognize individual species.

Another exciting characteristic about Baculites is that the females are usually two or three times bigger than their male counterparts. 

The former may have also had thicker ribbing on the shell surface.

Habitat and Distribution

Based on shell isotope studies, researchers have deduced that Baculites may have lived in the middle section of the water column, somewhere not too close to either the surface or bottom of the ocean. 

These cephalopods were also primarily found in some rock deposits, and it is possible that they lived in great shoals. 

Still, there are reasons for scientists to believe that Baculites did not occur so densely as other extinct straight-shelled cephalopods, like orhtocerid nautiloids, which lived much earlier than Baculites

Fossils were found in several areas in North America, including South Dakota, Wyoming, and some key locations in Europe. Overall, Baculites were widely distributed worldwide. 

The type species of Baculites, Baculites vertebralis, is regarded as one of the last ammonite species. 

Its fossils were found in Netherlands and Denmark, and studies have shown that this was the species that survived the mass extinction event, although its existence was limited to the Danian Age.

Behavior and Diet

Baculites fossils from South Dakota
Baculites fossils from South Dakota | DanielCD via Wikipedia CC BY-SA 3.0

Studies conducted on Baculites fossils reveal that this species probably fed on pelagic zooplankton as their primary diet. 

This conclusion was based on the remains of a pelagic isopod and larval gastropod found in the cephalopod’s mouth. 

And like other typical ammonites, Baculites may have also preyed on some slow-swimming animals like ostracods, foraminifera, bryozoa, and small crustaceans.

Life Cycle

Baculites from the Late Cretaceous of Wyoming
Baculites from the Late Cretaceous of Wyoming | Wilson44691 via Wikipedia CC BY-SA 3.0

There is no data revealing the life cycle of Baculites or how long they lived since there are no living ammonites to observe. 

Although there are still nautiluses in the world today, the differences between both species make it challenging to use the nautiluses’ life span to measure that of the ammonites. 

For example, living nautiluses thrive in deep, cold water, while ammonites prefer warm, relatively shallow water, which means they could have had a higher growth rate than nautiluses.

However, paleontologist Otto Schindewolf published an article on a Jurassic ammonite similar to present-day tubeworms. 

His study of tubeworms concluded that individual whorls on the ammonite shell took about four months to three years to grow. 

Since a true ammonite can have about a dozen whorls, we can conclude that ammonites, including Baculites, had a lifespan of 4 to 36 years. 

Still, there is no proof that tubeworms had the same growth rate as Jurassic ammonites.

Evolution and History

Baculites specimen
Baculites specimen | Wilson44691 via Wikipedia Public Domain

Baculites and other ammonite cephalopods are usually mistaken for othocerid nautiloid cephalopods, as both species share some similarities. 

For one, they are long and have a tubular form. 

However, it is apparent that both species existed at different times in the prehistoric era and evolved the tubular structure differently. 

The othocerid nautiloid cephalopods existed during the Paleozoic Era and probably went extinct in the Early Cretaceous Period. 

Baculites, on the other hand, were creatures of the Late Cretaceous Period. 

And although the fossils of both cephalopods bear some similarities, there are some distinguishable features like the suture line. 

Orhtocerid nautiloids have simple suture lines, while Baculites and other related ammonoids have intricately folded suture lines.

Cultural Significance

A fossil cast of the shell of a Baculites grandis on display at the North American Museum of Ancient Life in Lehi, Utah.
A fossil cast of the shell of a Baculites grandis on display at the North American Museum of Ancient Life in Lehi, Utah | Ninjatacoshell via Wikipedia CC BY-SA 3.0

Baculite fossils are highly fragile, especially along the suture line. 

Most fossils are never found as a whole; they are usually found in half or several broken pieces. 

Chambers broken across the suture line are often called stone buffaloes because of their appearance.

The first species of Baculites described in the Americas, Baculites ovatus, was a single specimen found in the Navesink Formation in Atlantic Highlands, New Jersey, and was described by Thomas Say in 1820. Samuel George Morton finally published an etching of the specimen in 1828.

Following the death of the specimen’s owner, Scientist Reuben Haines III, in 1831, this particular species went missing for almost 200 years until it was finally found by Matthew Halley in 2017 at Haines’s home, the historic Wyck House.

You can find the fossils in some famous museums worldwide, and shells are also available for sale for anyone interested in acquiring one or several of this prehistoric creature’s keepsakes.


Baculites is a unique cephalopod, especially considering that it was one of the few species that survived an event that wiped out a large portion of the world’s flora and fauna during the prehistoric era. 

Although not much has been revealed about this creature, we have enough information to understand how they thrived during the Late Cretaceous Period.


What is the Difference Between Orthoceras and Baculites?

Orthoceras lived in the Middle Ordovician Period, while Baculites lived in the Late Cretaceous Period. Besides that, both species are distinguishable by their suture lines.

Did Baculites Have Eyes?

Baculites, like typical ammonites, should have had large eyes to locate prey, and they were most likely fast creatures thanks to their hydrodynamic shells with tapered edges.


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