Image of Bat from the Narmer Plate
Bat is a very ancient goddess; the earliest evidence of her dates to the late Pre-Dynastic period. She was a cow-goddess of the sky with the power to see the past and into the future. This ability is referred to in the Pyramid Texts, where she was called "Bat, with her two faces." The deceased pharoah associated himself with Bat in this form. Later, she seemed to be the personification of the sistrum.
Bat was the chief deity for centuries in the 7th nome of Upper Egypt. During the Middle Kingdom, she was superseded by Hathor, who dominated the 6th nome - just next door.
Bat was not depicted very often in Egyptian artwork, however she was more commonly seen in amulets. She was shown as a woman with a human face, bovine ears and curly horns which emerged from her temples. She is most likely the cow-goddess seen at the top of the famous Narmer palette, which celebrated the unification of Upper and Lower Egypt. Bat is also famously seen on a unification pectoral in which she, as a sistrum), sits between Horus and Seth. Horus and Seth were the gods of Upper and Lower Egypt. Her image influenced the cult of Hathor.
From: hereBat was a cow goddess in Egyptian mythology depicted as a human face with cow ears and horns. By the time of the Middle Kingdom her identity and attributes were subsumed within the goddess Hathor.
The worship of Bat dates to earliest times and may have its origins in Late Paleolithic cattle herding. Bat was the chief goddess of Seshesh, otherwise known as Hu or Diospolis Parva, the 7th nome of Upper Egypt.
The epithet Bat may be linked to the word ba with the feminine suffix 't'. Ba means something like personality or emanation and is often translated as 'soul' . The word can also be read as 'power' or 'god'. Bat became strongly associated with the sistrum and the center of her cult, was known as the 'Mansion of the sistrum'.
The sistrum is a musical instrument whose shape is very similar to that of the ankh. This instrument is depicted with her head and neck as the handle and base, with rattles placed between her horns. The imagery is repeated on each side, having two faces. The sistrum was one of the most frequently used sacred instruments in temples.
The Egyptian Pyramid Texts say:
I am Praise; I am Majesty; I am Bat with Her Two Faces; I am the One Who Is Saved, and I have saved myself from all things evil. 
Although it was rare for Bat to be clearly depicted in painting or sculpture, two exceptions are displayed below, one in bovine form and the other in human form. In rare instances she was pictured as a celestial bovine creature surrounded by stars. More commonly, Bat was depicted on amulets, with a human face, but with bovine features, such as the ears of a cow and the inward-curving horns of the type of cattle first herded by the Egyptians.
She is found, on a significant Egyptian archaeological find shown to the right. This stone object dates from about the 31st century BC and contains some of the earliest hieroglyphic inscriptions. It is thought by some to depict the unification of Upper and Lower Egypt during the first dynasty under the pharaoh Narmer. Bat appears at the top of each side of the object.
The imagery of Bat as a divine cow was remarkably similar to that of Hathor the parallel goddess from Lower Egypt. The significant difference in their depiction is that Bat's horns curve inward and Hathor's curve outward slightly. It is possible that this could be based in the different breeds of cattle herded at different times.
From: WikiBat is one of the cow goddesses, particularly of Upper Egypt. She is hardly ever depicted in Egyptian art, though we find her more often in jewelry such as amulets head is human but the ears are bovine and horns grow from her temples. Her body is in the shape of a necklace counterpoise. In fact, the whole iconography suggests the sacred rattle or sistrum, which is fittingly since her cult center is the district of Upper Egypt known as the "Mansion of the Sistrum".
Without inscriptional evidence there must always be an element of caution but it does seem likely, on stylistic grounds, that she was represented on the top corners of the Narmer Palette, rather than Hathor, making her a very old Egyptian deity. Our earliest written evidence for the goddess is in the Pyramid Texts, which would support this view. Here, the king is Bat "with her two faces". Even earlier, she may be the goddess depicted on a palette on which stars are represented at the tips of her horns, indicating that, like most Egyptian cow deities, she has celestial connections.
It is possible that Bat has a presence that maintains the unity of Egypt, both north with south and the Nile Valley with the deserts. In addition to her pre-eminent position on the Narmer Palette, she is represented in the center of a pectoral of the 12th Dynasty flaked by the two protagonists in the struggle for the Egyptian throne, Horus and Seth, in a state of reconciliation. However, her similarity to Hathor, the cow goddess worshipped in the neighboring southern district, was so close that Bat's personal identity was not strong enough to survive being totally assimilated to her by the New Kingdom.
Primeval deity from the 7th Upper Egyptian Nome, it is probably her who is depicted on the Narmer Palette (ca 3100) with cow's horns and two faces. Her cult center seems to have been in the 7th Nome of Upper Egypt. The name of Bat is thought to be the feminine form of the word 'b3'; soul. In Utterance 506 (§1095), the king identifies himself with 'Bat with Her two faces'. There are also references to the 'great wild cow'. There were strong connections between Het-Hert (Gr: Hathor) and Bat, though they had differing origins. As their iconography showed such likeness, it has created quite some confusion among scholars.
Bat -- article