What is a Post-Anal Tail?

What is a Post-Anal Tail?

A tail-like structure originating from the anal mucocutaneous junction. This can cause a lot of pain for your cat when they are pooping. It can also cause impacted, hard masses that your vet has to manually squeeze out.

Animals that belong to the phylum Chordata share five key features (synapomorphies) during development: a notochord, a dorsal hollow nerve cord, an endostyle or thyroid, pharyngeal slits, and a post-anal tail.

Definition

In the animal kingdom, a post-anal tail is a movable extension of the posterior end of the body that extends past the alimentary canal. This tail is primarily used for balance and locomotion. Reptiles, amphibians, and fish have this type of tail while birds and mammals do not.

The post-anal tail is one of the five characteristics that distinguish chordates from non-chordates (the rest of the Bilateria). Other chordate traits include a dorsal hollow nerve cord, pharyngeal pouches, and a notochord flanked by somitic mesoderm that develop into segmental musculature and vertebral elements in some animals.

Some terrestrial vertebrates have tails that help them with balance, courting, and signaling when danger is near. The limbs of the backbone can also be used as a tail for movement. The anal tail is usually reduced in humans and great apes to a vestigial coccyx (tail bone) that aids in balance while sitting.

Arthropods (such as insects, crabs, and spiders) do not have a post-anal tail but some of these animals do have structures at the end of their abdomens that resemble a tail. The movability of these extensions anal tail is due to muscles in combination with flexibility. This is why many people mistakenly assume that all insects and other arthropods have a post-anal tail.

Origin

A post-anal tail is the posterior elongation of a chordate’s body that extends past the anus. It is muscular and helps with balance and locomotion in aquatic species and terrestrial vertebrates. It also contains skeletal elements. There are several theories about how this structure evolved.

A tail is one of the four key characteristics that distinguish vertebrates from other chordates and the remaining Bilateria. It consists of a dorsal hollow nerve cord, notochord flanked by somitic mesoderm from which segmental musculature develops in some vertebrates and an anus. The origin of the anus and tail is a subject of debate.

The most accepted theory is that the anal bud and its organizer cells are derived from the late blastoporal lip. This is supported by the fact that the posterior region of Xenopus embryos retains organizer activity and is recruited to form the tail (Gont & Tucker 1995a, b).

Another theory is that the anal bud develops from the presomitic mesoderm and fuses with the notochord. This is based on the fact that genes that are expressed in the anal region differ from those that are transcribed in other parts of the embryo. Moreover, the anal bud has a different cell fate than the head and trunk (Hejnol and Martindale 2009). Nevertheless, neither of these theories adequately explains why the anal lobe is distinct from the rest of the embryo.

Function

The tail distinguishes vertebrates and Anal manufacturers their fellow chordates from the rest of Bilateria, and it provides a window into processes that shape the entire body. It comprises a dorsal hollow neural tube, a notochord flanked by somitic mesoderm (from which segmental musculature and the vertebral column arise in some vertebrates), and pharangeal slits.

In most vertebrates, the pharangeal slits develop into gill arches in bony fish, and they develop into the jaw and inner ear in terrestrial animals such as reptiles, amphibians, and mammals. These adaptations reflect the functional role of the pharangeal slits in filter feeding: water is drawn into the mouth and passed down the alimentary canal to be expelled through the pharangeal slits, thus filtering out food particles.

All chordates possess the five distinct characteristics that define them as members of a unique group: a post-anal tail, pharangeal pouches, a dorsal hollow nerve cord, a notochord, and segmented body musculature. The ancestors of the chordates were invertebrates, but these animals later evolved to become tetrapods (four-legged vertebrates). This phylum includes crocodiles, frogs, birds, and mammals. In humans, the post-anal tail is reduced to a vestigial coccyx that aids in balance during sitting. In other animals, the post-anal tail has evolved into a movable muscular structure that helps in balance and courting. Click for a video discussing the evolution of these five characteristics that all chordates share.

Variations

There are a lot of different options when it comes to tailed butt plugs. They can be made out of steel, glass, soft fur and even rubber. The important thing is to find one that fits your kink and feels comfortable when inserted. They often need to be worn for long bouts of pet play or sub-dominant BDSM sessions so they need to be very comfortable.

Another important factor is the material. Most tailed butt plugs are made out of a material that is warm to the touch and requires less lube than others. They can also be made with a hilly or smooth texture depending on your personal preference. Finally, you want to make sure that the anal tail is able to fit in your anus without pinching or digging into it too much.

Heterodont teeth (teeth that are differentiated into incisors, canines, premolars and molars) and the post-anal tail are characteristics that classify mammal species as chordates. However, not all mammals have either of these characteristics. For example, scorpions and earthworms are non-chordates because they do not have the heterodont tooth feature, but they still have the post-anal tail. This suggests that the post-anal tail is an evolutionary vestige from chordates. Nevertheless, it is a very useful mechanism for balance and locomotion in aquatic vertebrates such as fishes.