I don't know why we see Goddess Durga sometimes sitting on a lion and sometimes on a tiger? Which animal was actually Durga's mount (vahana)? Is it Tiger or Lion?
Durga rides on a lion. The story is told in this chapter of the Devi Mahatmya of the Skanda Purana. Durga was created out of the combined energies of Brahma, Vishnu, Shiva, and other gods. And after she was created, the gods have her a variety of weapons and other ornaments:
The bearer of Pinaka (Siva) drawing forth a trident from his own trident presented it to her; and Visnu bringing forth a discuss out of his own discuss gave her. Varuna gave her a conch, Agni a spear; and Maruta gave a bow as well as two quivers full of arrows. Indra, lord of devas, bringing forth a thunderbolt out of (his own) thunderbolt and a bell from that of his elephant Airavata, gave her. Yama gave a staff from his own staff of Death and Varuna, the lord of waters, a noose ; and Brahma, the lord of beings, gave a string of beads and a water-pot. Surya bestowed his own rays on all the pores of her skin and Kala gave a spotless sword and a shield. The milk-ocean gave a pure necklace, a pair of undecaying garments, a divine crest-jewel, a pair of ear-rings, bracelets, a brilliant half-moon (ornaments), armlets on all arms, a pair of shining anklets, a unique necklace and excellent rings on all the fingers. Visvakarman gave her a very brilliant axe, weapons of various forms and also an impenetrable armour. The ocean gave her a garland of unfading lotuses for her head and another for her breast, besides a very beautiful lotus in her hand. The (mountain) Himavat gave her a lion to ride on and various jewels. The lord of wealth (Kubera) gave her a drinking cup, ever full of wine. Sesa, the lord of all serpents, who supports this earth, gave her a serpent-necklace bedecked with best jewels. Honoured likewise by other devas also with ornaments and weapons, she gave out a loud roar with a defying laugh again and again. By her unending, exceedingly great, terrible roar the entire sky was filled, and there was great reverberation. All worlds shook, the seas trembled.
So Himavat, the god of the Himalayas and father of Shiva's wife Parvati, is the one who gave Durga her lion.
I would definitely say that given the scriptural sources, the goddess has only the lion as her mount. But please note that iconographical instructions often give descriptions which are not strictly consistent with the stories. Again, sometimes painters and iconographers take liberties. While the Devimahatmya categorically mentions the lion as the goddess's only vehicle, there are beautiful Pahari paintings where she is fighting Mahishasura while riding on a tiger. Famous Sanskrit scholar Alf Hiltebeitel has also remarked that if one goes by the actual representations of the goddess over the centuries, then the lion and the tiger seem interchangeable as her vehicle. Moreover, scholars have also argued that a half-tiger and half-woman figure inscribed on an Indus seal is actually a prototype of the goddess riding on a tiger, thus hinting that the goddess's association with the tiger predates her association with the lion, and dates back to prehistoric times when Hindu mythology didn't exist in its Classical form.
The various manifestations of Bhagavatî Durgâ(Mahâdurgâ, Jayadurgâ, Vanadurgâ, Shûlinîdurgâ, Chandikâ, Mahishamardinî) have the lion as their vâhana. There is no mention of Her riding a tiger in any scriptural text (Devîmâhâtmya, Devîbhâgavata Purâna, Kâlikâ Purâna, Mahâbhâgavata Upapurâna, Tripurârahasya, Shâkta sections of Skanda Purâna; Vâmana Purâna; Brahmavaivarta Purâna; Varaha Purâna; Shiva Purana, Lalitopakhâyanam). While worshipping, the lion is offered as Her seat by means of the Simhamantra. Even in some abhichâra prayogas She is depicted to be dancing on a buffalo or lion head. Even the Agni Purâna, which describes the procedure of depicting deities in icons, states the presence of lion as Her vâhana.
As per the Pûrvakhanda of Vâyavîya Samhitâ of Shiva Purâna, the tiger named Somanandî is the vâhana of Bhagavatî Pârvatî. And since many people outside the Shâkta circle assume that the wife of Bhagavâna Shiva & the mother of Bhagavâna Shiva are the same person; the tiger got superimposed over the lion in North India.
There is a huge confusion about devi riding tiger due to probably,
Shiv Purana, Section 7.1 - Vāyavīya-saṃhitā, Chapter 26 - The attainment of higher status by the tiger (vyāghra)
The goddess said:—
- Is this tiger that has resorted to me seen by you? He has guarded my penance grove from wicked animals.
- Dedicating his mind to me he worships me without thinking of anything else. There is nothing more pleasing to me than his protection.
- He shall be appointed as an official in my harem. Out of pleasure Śiva will grant him the post of Ganeśvara.
Chapter 27- Gaurī’s embellishment
- He was named Somanandin because Soma means Śiva and this tiger pleased Soma as well as Nandin.
Thus, now we know that Somanandi became the Gana of devi. But does that mean she rides over it? Let's take this example, Andhaka, Banasur, Tripurasura are all Ganas of Mahadeva. So, does that implies that Mahadeva rides over them? Atleast non of us could have seen that vigrahas.
Thus, Devi rides Simha. And this can be found in enumerated citations.
3rd Skandha, chapter 23, Shloka 21,
They began to argue “Who in this Lady, mounted on a lion? Whence has She so suddenly come?”
5th Skandha, chapter 9,
The mountain Himālyā gladly offered Her various gems and a beautiful lion, of a golden colour for Her conveyance.
Such examples that the lion aids devi is too found in Durga Saptashati in Madhyam and Uttam Charitras.
Lets take a look at some dhyan mantras-
Navdurga katyayani dyanam-
चन्द्रहासोज्ज्वलकरा शार्दूलवरवाहना ।
कात्यायनी शुभं दद्याद् देवी दानवघातिनी ॥
Here शार्दूल means lion.
Shodashbhuja Bhadrakali -
घण्टां परशुं मुशलं विभ्रतो वामपाणिभिः ।
सिंहस्था नयनै रक्तवर्णैस्त्रिभिरभिज्ज्वला ॥
Ashtadashbbuja bhadrakali dhyan-
सिंहोस्योपरि तिष्ठन्ती व्याघ्रचर्मणि कौशिकी ।
विभ्रती रूपममतुलं ससुरासुर मोहनम् ॥
वन्दे वांछित लाभाय चन्द्रार्धकृत शेखरम्।
सिंहारूढा चंद्रघंटा यशस्वनीम्॥
विद्युद्दामसमप्रभां मृगपतिस्कन्धस्थितां भीषणां कन्याभिः करवालखेटविलसद्धस्ताभिरासेविताम्।
Here मृगपति means Lion, स्कंध means shoulders, thus the one sitting on shoulders of lion.
Since, I can't cite so many dhyana mantras over here, lets take look at paintings which are indeed made from Shastrokat dhyaan mantras-
Left to right- 1.Ashtabhuja Durga, 2.Angala Parmeshwari, 3.Lalita devi riding koti koti simhas in war against Bhanda(as per Lalitopkhyanam), 4.Jataveda Durga, 5.Shoolini Durga, 6.Adya devi, 7.Manonmani, 8.Kolhapur Mahalaxmi(mula prakriti of Saptashati), 9.Banashankari (Shakambhari), 10. Shodashbhuja Bhadrakali, 11.Ashtadashbhuja Ugrachanda, 12.Dashbhuja Katyayani.
Left to right- 1.Vimala devi of Puri Shaktipeeth, 2.Ashtadashbhuja Mahalaxmi, 3.Vanadurga, 4.Dhakeshwari(now in WB), 5.Kamakhya, 6.Tuljabhavani(Tuljapur), 7.Kanakdurga(Vijaywada), 8.Shiv Kutumba, 9.Vindhyavasini, 10.Jagadhatri, 11.Pratyangira, 12.Raksha Kali.
So, the motto to show all these images was that in all these 24 images none of the deities ride a tiger. All are seen with a lion indeed.
You can also add to this list, Saptashrungi, Ambaji, Kushmanda, Vaishnodevi(Rudra sundri/ Agni durga), Tara, Varahi, even folk deities such as Karni maa rides lion, and such many more to go.
Thus, concluding devi indeed as Vyagra as her gana, but that doeChapter plies that she rides it.
(Ps- credits to respective artists for the arts used as reference here.)