The shortnose gar possesses a prehistoric appearance that captures the imagination. With its torpedo-like body and elongated head containing a row of sharp, conical teeth, the gar is an unmistakable predator. Its body is covered in rows of interlocking, rhomboidal ganoid scales, providing an exceptional protective and flexible armor. These scales harken back to the ancient Paleozoic and Mesozoic actinopterygians, making the shortnose gar a living relic of the past.
The coloration of the shortnose gar is remarkable. It transitions from brown or olive green on the dorsal surface to yellow on the sides and white on the underbelly. This combination allows the gar to blend effectively with its surroundings, making it a stealthy predator.
Shortnose gar are predominantly found in calm waters, favoring large rivers and their backwaters, oxbow lakes, and quiet pools. They often inhabit areas near vegetation or downed logs, utilizing these structures for cover and ambush purposes. One remarkable adaptation of the gar is its ability to survive in environments with low oxygen levels and turbid conditions, owing to its specialized gas bladder. This gas bladder enables the gar to extract and utilize oxygen from swallowed air, resembling a lung and contributing to its survival in challenging habitats.
Shortnose gar engage in breeding activities during the spring months of April, May, and June when water temperatures range between 16 and 21 °C (61 and 70 °F). Females, accompanied by multiple males, scatter large, yellowish-green eggs in shallow, quiet water near submerged vegetation or other underwater structures. These eggs are held together in clumps by a sticky adhesive. After an incubation period of eight to nine days, the toxic eggs hatch, and the young remain attached to the yolk sac for an additional week. Once detached, they begin feeding on insect larvae and small crustaceans. Sexual maturity is typically achieved around three years of age, coinciding with a length of approximately 15 inches (380 mm).
Shortnose gar are formidable ambush predators, displaying exceptional efficiency in capturing their prey. While their primary diet consists of fish, they are opportunistic feeders and consume a variety of food sources. Crayfish, insects, and other invertebrates form a significant part of their diet. Interestingly, shortnose gar are known to consume more invertebrates than any other gar species. They have even exhibited territorial defense behaviors when foraging on high numbers of periodical cicadas, showcasing their adaptability and resourcefulness.
The shortnose gar is native to North America, primarily inhabiting the central United States. Its distribution spans the vast Mississippi and Missouri River basins, extending from Montana in the west to the Ohio River in the east. In the southern regions, shortnose gar can be found along the Gulf Coast, from Louisiana and Alabamato parts of Texas. This widespread distribution highlights the adaptability of the species and its ability to thrive in diverse aquatic ecosystems.
Shortnose gar play a crucial role in maintaining the equilibrium of ecosystems. By feeding on minnows and other destructive fish populations, they help regulate the balance of aquatic life. Additionally, shortnose gar are highly sought after as aquarium fish, making them popular among enthusiasts. Their unique appearance and behaviors make them a captivating addition to public aquariums across the country.
While shortnose gar populations generally remain plentiful due to their formidable armor and few natural predators, specific regions have raised concerns about their conservation status. In Montana, the restricted distribution and limited population sizes have led to the classification of shortnose gar as a species of special concern. Similarly, in Ohio, they are considered an endangered species due to their limited range, primarily centered around the Ohio River, lower Scioto River, and Great Miami Rivers. These designations highlight the need for conservation efforts to protect the species and its habitats.