I Can’t Sleep - Stingrays | Gentle Bedtime Reading for Sleep

Episode Date: September 12, 2025

Drift off with this calm bedtime reading that helps with sleep and eases insomnia. In this soothing episode, you’ll learn all about stingrays while letting your mind relax into gentle rest. Benjamin’s steady, peaceful narration shares fascinating facts about these graceful creatures of the sea, blending education with relaxation. There’s no whispering, no hypnosis—just calm storytelling designed to ease stress, anxiety, and sleeplessness. Press play, settle in, and let your thoughts drift away as you discover the world of stingrays. Happy sleeping! Read with permission from Stingray, Wikipedia (https://en.wikipedia.org/wiki/Stingray), licensed under CC BY-SA 4.0. Learn more about your ad choices. Visit megaphone.fm/adchoices

You're listening to a Glassbox Media podcast. What if I told you that most of the modern day self-help advice you've been hearing could actually make you worse? The key to a better life isn't about feel-good gimmicks that sound catchy. The Mentally Stronger Podcast gives you access to a licensed therapist who shares science-backed tools that will actually change your life. Hi, I'm Amy Morin, psychotherapist, mental strength trainer, and international best-selling author. In each episode, we cover research-back strategies, like how to stop relying on willpower and start creating habits for lasting change. And the five mental strength-building exercises you can do from your couch. I also speak to world-class experts like Dr. Nicole Kane, who shares how to permanently heal anxiety by addressing the root cause.

With over 200 episodes in our catalog, this podcast is for you if you're ready to crush self-doubt, conquer challenges, become stronger than ever with therapist-approved strategies that can change your life. Listen to Mentally Stronger with Therapist Amy Morin, wherever you get your podcasts. Welcome to the I Can't Sleep Podcast, where I help you drift off one fact at a time. I'm your host, Benjamin Boster, and today's episode is about stingrays. A special thanks to Carissa Jones for sponsoring today's episode. Sting rays are a group of sea rays, a type of cartilaginous fish. They are classified in the sub-order myleobatity of the order myleobataformis,

and consist of eight families. Exotriginity, six-skill stingray, pleasobatity, deep-water stingray, uralofity, stingarees, uralofity, stingaries, urotriginity, round rays, daisy-adity, whipped-tail stingrays, potamotriganity, river stingrays, chimnerity, butterfly rays, and myelobatity, eagle rays. There are about 220 known stingray species organized into 29 genera. Sting rays are common in coastal, tropical, and subtropical marine waters throughout the world. Some species, such as the thorn-tail sting ray, are found in warmer temperate oceans,

and others, such as the deep water stingray, are found in the deep ocean. The river stingrays and a number of whip-tail sting rays are restricted to freshwater. Most myelobatoids are demersal, inhabiting the next to lowest zone in the water column. But some, such as the pelagic sting ray and the eagle ray, are pelagic. Sting rays diverged from their closest relatives, the pan-rays, during the late Jurassic period, and diversified over the course of the Cretaceous and of the different extant families today. The earliest stingrays appear to have been benthic, with the ancestors of the eagle rays becoming pelagic during the early, late Cretaceous. Permaneralized stingray teeth

have been found in sedimentary deposits around the world, as far back as the early Cretaceous, the oldest known stingray taxon as Desiades Spetonensis, from the hot ravion of England, whose teeth most closely resemble that of the extant six-kills stingray. Although stingray teeth are rare on sea bottoms compared to the similar shark teeth, scuba divers searching for the latter do encounter the teeth. ease of stingrays. Full-body stingray fossils are very rare, but are known from certain Lagerstaden that preserve soft-bodied animals. The extinct cyclobatus of the Cretaceous of Lebanon has sought to be a skate that had convergently evolved a highly stingray-like body

plan. Although its extant taxonomic placement is still uncertain, true stingray fossils become more common and the Iocene, with the extinct freshwater stingrays, Heliobatus, and Astrogygon, known from the Green River formation. A diversity of stingray fossils is known from the Iocene Monte Balca formation from Italy, including the early stingery arequia, as well as Dezio myliobatus, which is thought to represent a transitional form between sting rays and eagle rays. And the highly unusual Lysinibatus, which had an extremely short and slender tail with no sting, the mouth of the stingray is located on the ventral side of the vertebrate.

Sting rays exhibit hyostilog jaw suspension, which means that the mandibular arch is only suspended by an articulation with the myomandibula. This type of suspension allows for the upper jaw to have high mobility and protrude outward. The teeth are modified placoid scales that are regularly shed and replaced. In general, the teeth have a root implanted within the connective tissue, and a visible portion of the tooth is large and flat, allowing them to crush the bodies of hard-shelled prey. Male stingrays display sexual dimorphism by developing cusps or pointed ends to some of their teeth.

During mating season, some stingray species fully change their tooth morphology, which then returns to baseline during non-mating seasons. Spiracles are small openings that allow some fish and amphibians to breathe. Stingray spiracles are openings just behind its eyes. The respiratory system of stingrays is complicated by having two separate ways to take in water to use the oxygen. Most of the time stingrays take in water using their mouth and then send the water through the gills for gas exchange. This is efficient, but the mouth cannot be used when hunting because the stingrays bury themselves in the ocean sediment and wait for prey to swim by.

So the stingray switches to using its spiracles. With the spiracles, they can draw water free from sediment directly into their gills for gas exchange. These alternate ventilation organs are less efficient than the mouth, since spiracles are unable to pull the same volume of water. However, it is enough when the stingray is, quietly waiting to ambush its prey. The flattened bodies of stingrays allow them to effectively conceal themselves in their environments.

Sting rays do this by agitating the sand and hiding beneath it. Because their eyes are on top of their bodies and their mouths on the undersides, stingrays cannot see their prey after capture. Instead they use smell and electroreceptors, similar to those of sharks. Stingray settle on the bottom while feeding, often leaving only their eyes and tails visible. Coral reefs her favorite feeding grounds and are usually shared with sharks during high tide. The stingray uses its paired pectoral fins for moving around. This is in contrast to sharks and most of their fish, which get most of their swimming power from a single caudal tail fin.

Stingray pectoral fin locomotion can be divided into two categories, undulatory and oscillatory. Sting rays that use undulatory locomotion have shorter, thicker fins for slower motile movements and benthic areas. Longer, thinner pectoral fins make for faster speeds in oscillation mobility and pelagic zones. Visually distinguishable oscillable oscillational. has less than one wave going, opposed to undulation having more than one wave at all times. Sting rays use a wide range of feeding strategies. Some have specialized jaws that allow them to crush

hard mollusk shells, whereas others use external mouth structures called cephalic lobes to guide plankton into their oral cavity. Benthic stingrays, those that result, on the seafloor are ambush hunters. They wait until prey comes near, then use a strategy called tenting. With pectoral fins pressed against the substrate, the ray will raise its head, generating a suction force that pulls the prey underneath the body.

This form of whole body suction is analogous to the bucle suction feeding performed by rayfinned fish. sting rays exhibit a wide range of colors and patterns on their dorsal surface to help them camouflage with a sandy bottom some stingrays can even change color over the course of several days to adjust to new habitats Since their mouths are on the underside of their bellies, they catch their prey, then crush and eat with their powerful jaws. Like its shark relatives, the stingray is outfitted with electrical sensors, called Ampuli of Lorenzini. Located around the stingray's mouth, these organs sense the natural electrical charges of potential prey. Many rays have jaw teeth to enable the brain. them to crush mollusks, such as clams, oysters, and muscles. Most stingrays feed primarily on

mollus, cretations, and occasionally on small fish. Freshwater stingrays in the Amazon feed on insects and break down their tough exoskeletons and mammal-like chewing motions. Large pelagic rays, like the manta, use ram-feeding to consume vast quantities of plankton, and a very large been seen swimming in acrobatic patterns through plankton patches. The venom of the stingray has been relatively unstudied due to the mixture of venomous tissue secretion cells and mucus membrane cell products that occurs upon secretion from the spinal blade. The spine is covered with the epidermal skin layer. During secretion, the venom penetrates the epidermis and mixes with the mucus

to release the venom on its victim. Typically, other venomous organisms create and store their venom in a gland. The stingray is notable in that it stores its venom within tissue cells. The toxins that have been confirmed to be within the venom are cystotins, paroxyrodoxin, and galactin. Galactin induces cell death in its victims, and cystotins inhibit defensive. enzymes. In humans, these toxins lead to increased blood flow in the superficial capillaries and cell death. Despite the number of cells and toxins that are within the stingray, there is little relative energy required to produce and store the venom. The venom is produced and stored in the

secretory cells of the vertebral column at the mid-distal region. These secretory cells are housed within the ventrolateral grooves of the spine. The cells of both marine and freshwater stingrays are round and contain a great amount of granule-filled cytoplasm. The stinging cells of marine stingrays are located only within these lateral grooves of the stinger. The stinging cells of freshwater stingray branch out beyond the lateral grooves to cover a larger surface area along the entire blade. Due to this large area and an increased number of proteins within the cells,

the venom of freshwater stingrays has a greater toxicity than that of marine stingrays. Sting rays are usually very docile and curious. Their usual reaction being to flee any disturbance, but they sometimes brush their fins past any new object they encounter. Nevertheless, certain larger species may be more aggressive and should be approached with caution. The giant oceanic manta ray, giant manta ray or oceanic manta ray, is a species of ray in the family mobility and the largest type of ray in the world. It is circumglobal and is typically found in tropical and subtropical waters, but can also be found in temperate

waters. Until 2017, the species was classified in the genus Manta, along with the smaller reef Manta ray. DNA testing revealed that both species are more closely related to rays of the genus Mubula than previously thought. As a result, the giant Manta was renamed Mubula by Rostras to reflect the new classification. The giant Oceanic Manta ray can grow up to a maximum of 9 meters in length and to a disk size of 7 meters across, with a weight of about 3,000 kilograms. But the average size commonly observed is 4.5 meters. It is dorso ventrally flattened, and has large triangular pectoral fins on either side of the disc. At the front, it has a pair of cephalic fins which are forward extensions of the pectoral fins. These can be rolled up in a spiral

for swimming or can be flared out to channel water into the large forward-pointing rectangular mouth on the animal's feeding. The teeth are in a band of 18 rows and are restricted to the central part of the lower jaw. The eyes and the spiracles are on the side of the head, behind the cephalic fins, and the gill slits are on the ventral under surface. It has a small dorsal fin, and the tail is long and whip-like. The manta ray does not have a spiny tail as to the closely related devil rays, but has a knob-like bulge at the base of its tail. The santa ray does not have a spiny tail. The skin is smooth with a scattering of conical and ridge-shaped tubercles. The coloring of the dorsal upper surface is black, dark brown, or steely blue, sometimes

with a few pale spots, and usually with a pale edge. The ventral surface is white, sometimes with dark spots and blotches. The markings can often be used to recognize individual fish. Mobula bairostrus is similar in appearance to Mobula alfredi, and the two species may be confused as their distribution overlaps. However, there are distinguishing features. The oceanic manta ray is larger than the reef manta ray, four to five meters in average, compared to three to three point five meters. However, if the observed rays are young, their size can easily bring. confusion. Only the color pattern remains an effective way to distinguish them.

The Reef Manta Ray has a dark dorsal side with usually two lighter areas on top of the head, looking like a nuanced gradient of its dark dominating black coloration and whitish to grayish. The longitudinal separation between these two lighter areas forms a kind of why. while for the oceanic manta ray, the dorsal surface is deep dark and the two white areas are well marked without grating effect. The line of the separation between these two white areas forms a T. The two species can also be differentiated by their ventral coloration. The brief manta ray has a white belly, often with spots between the bronchial gillslids and other spots spread across trailing edge. of pectoral fins, an abdominal region. The Oceanic Manda Ray has also a white ventral coloration

with spots clustered around lower region of its abdomen. Its cephalic fins inside of its mouths and its gillslids are often black. The giant oceanic mandoray has a widespread distribution in tropical and temperate waters worldwide. In the northern hemisphere, it has been recorded It is far north as Southern California and New Jersey in the United States, Al-Mari Prefecture and Japan, the Sinai Peninsula in Egypt, and the Azores in the Northern Atlantic. In the southern hemisphere, it occurs as far south as Peru, Uruguay, South Africa, and New Zealand. It is an ocean-going species and spends most of its life far from land, traveling with occurrence and migrating to areas where upwellings of nutrient-rich water increases the availability of zooplankton.

The oceanic manta ray is often found in association with offshore oceanic islands. When traveling in deep water, the giant oceanic manta ray swims steadily in a straight line. While further inshore, it usually basks or swims idly. Mantos may travel alone or in groups of up to 50. They sometimes associate with other fish species, as well as sea birds and marine mammals. About 27% of their diet is based on filter feeding, and they will migrate to coastlines to hunt varying types of zooplankton, such as copepods, mycids, shrimp, ephaciads, decapod larvae,

and on occasion varying sizes of fish. When foraging, it usually swims slowly around its prey, hurting the plankton creatures into a tight group before speeding through the bunched-up organisms with its mouth open wide. While feeding, the cephalic fins are spread to channel the prey into its mouth, and the small particles are sifted from the water by the tissue between the gill arches. As many as 50 individual rays may gather at a single plankton-rich feeding site. Research published in 2016 proved about 73% of their diet as mesopalagic deep water sources, including fish.

Earlier assumptions about exclusively filter feeding were based on surface observations. The giant oceanic manta ray sometimes visits a cleaning station on a coral reef. where it adopts a near stationary position for several minutes, while cleaner fish consume bits of loose skin and external parasites. Such visits occur most frequently at high tide. It does not rest on the seabed as do many flat fish, as it needs to swim continuously to channel water over its gills for respiration. The oceanic manta has one of the largest brains,

weighing up to 200 grams, five to ten times larger than a whale shark brain. It heats the blood going to its brain and is one of the few animals, land or sea, that might pass the mirror test, seemingly exhibiting self-awareness. The giant freshwater stingray is a species of stingray in the family, Dacieti. It is found in large rivers and estuaries in Southeast Asia, and Borneo, though historically it may have been more widely distributed in South and Southeast Asia. The widest freshwater fish and the largest stingray in the world, this species grows up to 2.2

meters across and can exceed 300 kilograms in weight. It has a relatively thin oval pectoral fin disc that is widest anteriorly, and a sharply pointed snout with a protruding tip. Its tail is thin and whip-like, and lacks fin folds. This species is uniformly grayish-brown above and white below. The underside of the pectoral and pelvic fins bear distinctive, wide, dark bands on their posterior margins. Bottom dwelling in nature, the giant freshwater stingray inhabits sandy or muddy areas, and, and, and, and, and, and preys on small fishes and invertebrids. Females give live birth to litters of one to four pubs,

which are sustained a term by a maternally produced histotroph. The first scientific description of the giant freshwater stingray was authored by Dutch exeologist Peter Blaker. In an 1852 volume of the journal, Verhandlingen von Ut-Battavius Knotskamp von Kuntzkaep van Kuntzkappen. His account was based on a juvenile specimen 30 centimeters across, collected from Jakarta, Indonesia. Blaker named the new species polylipus,

from the Greek polymene and lepus scales, and assigned it to the genus Trigon. However, in subsequent years, Blaker's description was largely overlooked, and in 1990, the giant freshwater stingray was described again, by Sue Bob Mankaprasid and Tyson Roberts in an issue of the Japanese Journal of Ix theology. They gave it the name Himantura Chopraya,

which came into widespread usage. In 2008, Peter Last and B. Mabel Manjaji Matsumoto confirmed that T. Polypsis and H. Choprya referred to the same species, and since Blaker's name was published earlier, The scientific name of the giant freshwater stingray became Himandra Palipsis. This species may also be called the giant freshwater whip ray, giant stingray, or freshwater whip ray. There's a complex of similar freshwater and estuarine stingrays in South Asia, Southeast Asia, and Australasia,

that are or were tentatively identified with eupolypsis. The Australian freshwater Eurogymnis were described as a separate species, Eurogimnis de Allensis, in 2008. The freshwater Eurogimnis in New Guinea are probably E. Delaunasis rather than Eupalaepsis. The confirmation awaits further study. Trigon fluviatilus from India has disdivis. described by Nelson Enandale in 1909, closely resembles and may be conspecific with Eupolypsis.

On the other hand, comparison of freshwater whip-ray DNA and amino acid sequences between India and Thailand has revealed significant differences. Finally, additional research is needed to assess the degree of divergence amongst populations of Eupolipsis, and has to beaulipsis, and has to be able to. inhabiting various drainage basins across its distribution, so was to determine whether further taxonomic differentiation is warranted. In terms of the broader evolutionary relationships between the giant freshwater whip ray and the rest of the family Deciadity, a 2012 phylogenetic analysis based on mitochondrial DNA, reported that it was most closely related to the porcupine ray, and that they in turn

formed a clade, with a mangrove whip ray and the tube-mouth whip ray. This finding adds to a growing consensus that the genus Himantura sensu-lato is paraphyletic. The giant freshwater stingray has a thin, oval, pectoral-fin disc, slightly longer than wide, and brought us towards the front. The elongated snout has a wide base and a sharply pointed tip that projects beyond the disc. The eyes are minute and widely spaced. Behind them are large spiracles.

Between the nostrils is a short curtain of skin with a finely fringed posterior margin. The small mouth forms a gentle arch and contains four to seven palpoli, two to four large at the center and one to four small to the sides on the floor. The small and rounded teeth are arranged into pavement like bands. There are five pairs of gillslids on the ventral side of the disc. The pelvic fins are small and thin.

Mature males have relatively large claspers. The thin cylindrical tail measures 1.8 to 2.5 times as long as the disc, and lax fin folds. A single serrated stinging spine is positioned on the upper surface of a tail near the base. At up to 38 centimeters long, the spine is the largest of any stingray species. There is a band of hard-shaped tubercles on the upper surface of the disc, extending from before the eyes to the base of the sting. There is also a midline row of four to six and six.

large tubercles at the center of the disc. The remainder of the disc upper surface is covered by tiny granular denticles, and the tail is covered with sharp prickles past the sting. This species is plain, grayish, brown above, often with a yellowish or pinkish tint towards the fin margins. In life, the skin is coated with a layer of dark brown mucus. The underside is white with broad, dark bands, edged with small spots on the trailing margins of the pectoral and pelvic fins. The tail is black behind the spine. The giant freshwater stingray reaches at least 1.9 meters in width and 5 meters in length, and can likely grow larger, with reports from the Macong and Chaupraya rivers of individuals weighing 500 to 600 kilograms, but it is not a very much.

not impossible that it is 1,500 kilograms, or even 2,000 kilograms. It ranks among the largest freshwater fishes in the world. In June 2022, it was reported that a specimen caught in the Macong River had broken the record for the largest strict freshwater fish ever documented. The largest sturgeon species can far exceed the size, but they are an adrimous. The individual weighed 661 pounds or 300 kilograms and was measured at 3.98 meters long and 2.2 meters wide.